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Plant breeding is the process in which two plants of two different varieties, species, and genera with desired traits are crossed to get those desired traits in a particular plant species. This process of plant breeding is also referred to as:

hybridization as the new plant formed is a hybrid of the two different plants having desired characteristics into it. 

This crossing is called intervarietal when it is in two different varieties, interspecific when it is in two different species and intergeneric when it is in between two different genera. 

The desired characteristics that are seen before breeding are resistance towards diseases, high yield, good absorption of fertilizers, quality of the product etc.

Exotic (foreign) breed of cattle’s are preferred for long lactation period while indigenous (local) breeds are highly disease resistance. Hence cross breeding of the different breed cattle’s will generate the cattle with both the desirable needs.

It is growing of two or more crops simultaneously on the same piece of land. It is also known as multiple cropping. This type of cropping leads to an improvement in the fertility of the soil and hence increase in crop yield because when the two crops are properly chosen, the products and refuse from one crop help in the growth of the other crop plant and vice-versa. Mixed cropping is an insurance against crop failure due to abnormal weather and plant pests. Soyabean + pigeon pea, Maize + urad dal (black gram),Groundnut + sunflower ,Wheat + Chick Pea. 

Advantages of Mixed cropping: 

• No risk of crop failure, 
• Increase in yield, 
• Improvement in soil fertility 
• Minimizing Pest Damage.

Food is needed by all organisms for many purposes : 

1. The main function of food is to help in growth. 

2. Food provides energy for movements such as running, walking or raising our arm. 

3. Food is also needed for replacement and repairing damaged parts of body. 

4. Food gives us resistance to fight against diseases and protects us from infections.

Manure : 

• It is a source of organic matter. 

• It supplies small quantities of nutrient to the soil. 

• It is prepared by the decomposition of animal excreta and plant waste. 

Various forms of Manures : 

(A) Compost : The process in which animal excreta (like cow dung), kitchen waste, plant remains, waste food, sewage waste etc. are decomposed in pits is known as composting. 

(B) Vermicompost : Compost prepared by using earthworms to hasten the process of decomposition of plants and animals refuse is called vermicompost. 

(C) Green manure : Some plants like sun hemp, guar etc. are grown and after sometime mulched by ploughing in the field. These green plants turn into green manures. They are rich in nitrogen and phosphorus.

Fertility of soil is maintained for a longer period and helps in pest and weed control.

Crops are chosen whose nutrient requirements are different so that maximum utilisation of the soil nutrients takes place. Also, their water needs, rooting patterns etc are different. Besides the advantages mentioned for mixed cropping,

Intercropping has the following additional advantages: 

• Application of pesticides and fertilizers is more convenient due to well defined patterns of crops. 
• Harvesting of crops is also easier.

Legumes are desired in crop rotation because leguminous plants form a symbiotic association with the Rhizobium and this symbiotic association help in nitrogen fixation. These leguminous plants replenish the nitrogen in the soil and thus reduce the amount of fertilizers that need to be used. 

Since, leguminous plants improve the amount of nitrogen present in soil; it is always desired to grow legumes in crop rotation.

Crop rotation is a process in which different crops are grown on the same piece of land according to a previous set model. In this type of crops to be grown are decided according to different environmental conditions like temperature, sunlight, irrigation facilities etc. 

The benefit that we have in crop rotation is that we can have more than two crops in a year with good yield. 

Also, as different crops are grown there will be replenishment of the nutrients as a nutrient requirement of each crop differs from the other. Growing same crop, again and again, makes land deficient in that particular nutrient. So, in order to keep the land nutrient rich and having a good yield of different crops, we must adopt crop rotation.

Inter-cropping and crop rotation both play an important role in increasing the yield of crops.

Inter-cropping is a farming method that involves planting or growing more than one crop at the same time and on the same piece of land. 

1. Inter-cropping gives higher income per unit area than sole cropping. 

2. It acts as an insurance against failure of crop in abnormal year. 

3. Inter-crops maintain soil fertility as the nutrient uptake is made from both layers. 

4. Reduce soil runoff. 

Crop rotation determines the successive arrangement of different crops in a particular order over several years in the same growing space. This process helps maintain nutrients in the soil, reduce soil erosion, and prevents plant diseases and pests. It also helps in controlling weeds and controls the growth of pathogens and pests in crops. 

Explanation- From the word itself it determines the use of different crops one by one on single land so that the nutrients consumed by 1st crop are not required for 2nd crop and will give time to the soil for replenishing itself with those exhausted and the remaining nutrients will help in the growth of 2nd crop.

With the increase in human population there is a growing demand for food resources which resulted in white revolution. Increased maintenance and hygiene of animals in their food and living lead to higher production. Also new animal variety improvement methods lead to more animal production with better qualities.

(i) Apis dorsata: the rock bee; Apis lorae: the little bee; and Apis cerena indica: the Indian bee. 

(ii) An Italian bee called Apis mellifera has been used to increase the yield of honey because: 

a) They have high honey collection capacity. 

b) They can stay in a beehive for the much longer period and show a higher rate of breeding. 

(iii) The value(taste) of honey depends on the pasturage or, the lowers available to the bees for nectar and pollen collection.

Intercropping is the agricultural practice of cultivating two or more crops in the same space at the same time in a definite pattern. Row- type intercropping cropping involves the component crops arranged in alternate rows. This may also be called alley cropping. 

A variation of row cropping is strip cropping, where multiple rows (or a strip) of one crop are alternated with multiple rows of another crop. Intercropping also uses the practice of sowing a fast growing crop with a slow growing crop, so that the fast growing crop is harvested before the slow growing crop starts to mature.

In poultry, the improved varieties are developed for improving the quality and quantity of chicks. And among fishes, composite fish cultures should use so that they do not compete for food among them having different types of food habits.

Factors for which variety improvement in crops is done:

(a) Higher yield : To increase the productivity of the crop per acre. 

(b) Improved quality : Quality of crop products vary from crop to crop. 

(c) Biotic & Abiotic resistances : Crop production reduces due to biotic and abiotic factors. Varieties resistant to these factors can improve crop production. 

(d) Wider adaptability : Crops which can grow in different conditions, will help in setting high production. 

(e) Desired agronomic traits : Crops which contain desired agronomic traits (height, branching, leafs), sets high production.

Criteria for crop selection: 

● Crops should have different maturation time. 

● Both crops should have different water requirements. 

● The nutrient requirement of one crop should be lesser than the other. 

● If one crop is deep rooted, the other has shallow roots. 

● If one crop is tall, other should be dwarf.

It determines the successive arrangement of different crops in a particular order over several years in the same growing space. This process helps maintain nutrients in the soil, reduce soil erosion, and prevents plant diseases and pests. From the word it self it determines the use of different crops one by one on single land so that the nutrients consumed by 1^st crop are not required for 2^nd crop and will give time to the soil for replenishing itself with those exhausted and the remaining nutrients will help in the growth of 2^nd crop.

Intensive fish farming can be done in composite fish culture system.

● Both local and imported fish species are used in such systems. 

● In such a system, a combination of five or six fish species is used in a single fishpond. These species are selected so that they do not compete for food among them having different types of food habits. 

● For example: Catlas are surface feeders, Rohu feeds in the middle zone of the pond, Mrigal and Common Carps are bottom feeders and Grass Carps feed on the aquatic weeds now they will not compete for the food. 

The problem was that most of these fishes breed only during rainy season. Hence the obstacle is to collect good quality seed, so that it can be collected and mixed with other species as well. 

To solve this problem hormonal stimulation is performed which involves the activities that lead to the maturation of the fish sex cells to breed these fishes in pond.

Inter-cropping is growing two or more crops simultaneously on the same field in a definite pattern.

1. From natural process.

2. By fish farming which is called culture fishery.

Climate change can disrupt food availability and soil factors like soil moisture, soil temperature.

Weeds contain different spines secreting poisonous and toxic substances but same thing does not happen in case of weeds. 

Weeds affect crop yield in an adverse manner. They compete with the crop for space, sunlight, nutrients, water and thus affect the growth of crop in an adverse manner. Since, crops do not get enough space, nutrients; water due to weeds their growth is retarded and thus yields is also reduced. 

Weeds are removed by the following ways: 

• By using herbicides weeds can be removed. 
• By mechanical method of removing weeds manually. 
• By adopting crop rotation and growing crops timely.

Xanthium (Gokhroo), Amaranthus (Chaulai) are the names of two weeds (these are unwanted plants in the cultivated ield).

Weeds are referred to as unwanted plants growing in a land.

Weeds compete for food, space and light. They take up the plants nutrients and reduce the growth of the crop. They may sometimes produce toxic substances which may interfere with crop growth. During harvesting, weeds get mixed up with crop to lower down its quality. Hence statement C is correct.

Weeds are unwanted plants which are grown on along with crops.
Eg: Xanthium, parthenium etc.

Diseases are transmitted in crops through bacteria, fungi, and viruses etc. These pathogens like bacteria, fungi, and viruses remain present in the soil, water, air and through this they enter the plant body and cause various diseases.

Weeds are unnecessary and unwanted plants which grow by themselves in the fields. 

For example- Xanthium, Parthenium are some examples of weeds. 

They cause damage to the crops because they compete with the crops for space, nutrition, water, sunlight and in this manner affect the growth of our crops and thus damage them.

i. Regular cleaning of farms. 

ii. Prevention and cure of the diseases.

Pisciculture or fishery is an industry devoted to the catching, processing or selling of fish, shellfish or other aquatic animals. The rearing of aquatic animals or the cultivation of aquatic plants for food is called aquaculture. .

Inland fisheries involve fresh water canals, ponds, reservoirs, rivers from which fish are captured.

Estuaries are the regions where fresh water mixes with sea water. These are rich sources of fish. Fish farming encounters the problem of lack of quality seed or eggs. Fish are bred in ponds by hormonal stimulation. Fish are injected with hormones that stimulate the production of eggs or seed. This ensures the supply of pure fish seed in desired quantities.

Types of fishery are:

(a) Fin fishery and Shell fishery

(b) Capture fishery and culture fishery

(c) Marine fishery and Inland fishery

(a) Fin fishery and Shell fishery

Fish production involves fin fishery and shell fishery. Two main species of finned true fish are Catla and Rohu, and that of shellfish such as prawns and mollusks.

(b) Capture fishery and culture fishery

Fish are obtained by capture fishing as an economic source for their meat.

• Capture fishing involves capturing of fish from sea water or fresh water. Culture fishing involves culturing the fish in small enclosures.
• Capture fishing is classified into marine fishery and inland fishery depending upon the resources used for fishing.

Culture fishery involves rearing of fish in small structures like wells.

• Fish farming can be done in the rice field where both grains and fish can be harvested from the farm.
• As feeding habits of fish differ from species to species, many varieties can be reared on the same farm. Composite fish farming is rearing of different varieties of fish in the same area. e.g. Composite fish farming includes Catla, the surface feeders, Rohu, feed in the middle zone of a pond, Mrigal and common carp, the bottom feeders, and grass carp, feeding on weeds. These species can co-exist in a single pond, and thus, increase the yield of fish from the pond.

(c) Marine fishery and Inland fishery

• Mariculture is the culture of fish in marine water.
• Marine fishery involves fishing in salt water regions.
• Some examples of marine fish are Pomphret, Tuna and Mackerel.
• Fish are captured by locating large schools of fish, in the open sea, with the help of satellites and echo-sounders.
• Marine fish of high economic value are farmed in seawater. Shellfish, such as prawns, mussels and oysters are also farmed in seawater. Oysters are cultivated for their pearls.

The best quality of pearl is obtained from Marine oysters.

Oysters are cultivated for the pearls they make inside them as they are of high economic value.

Fever along with spasms in hands and legs are the symptoms of polio disease

Female anopheles mosquito.

In chikungunya fever.

Aedes mosquito causes chikungunya – and dengue.

1. Spreading of seeds from one place to another place is called seed dispersal. 

2. Seed dispersal may happen through wind, water, animals, birds, man and even through some mechanical processes such as bursting of fruits.

Correct option is a. size of the orbital

Ethanoyl chloride is converted in to Ethanal. 

OR

CH₃COCl + H₂ + Pd-BaSO₄/S →  CH₃CHO + HCl 

Correct option is c. 3 2 -3 ½

Carboxylic acids are prepared by – 

a. Oxidation of primary alcohols, aldehydes and alkenes. 

b. Hydrolysis of nitriles 

c. Treatment of Grignard reagent with carbondioxide. 

(v) Assertion and reason both are correct statements but reasson is not correct explanation of assertion.

Aldehydes are prepared by

a. Dehydrogenation of primary alcohols 

b. Controlled oxidation of primary alcohols. 

c. Controlled and selective reduction of acylhalides 

Aromatic aldehydes can be prepared by

a. Oxidation of toluene with chromyl chloride or CrO₃ in the presence of acetic anhydride. 

b. Formylation of arenes with carbon monoxide and Hydrochloric acid in the presence of anhydrous aluminium chloride / Cuprous chloride. 

c. Hydrolysis of benzal chloride. 

Ketones are prepared by

a. oxidation of secondary alcohols 

b. Hydration of alkenes 

c. Reaction acyl chlorides with dialkyl cadmium 

d. By Friedel Crafts reaction 

Due to resonance, It does not have free carbonyl group.

(a)Concave mirror
(b) Convex lens
(c) Concave lens
(d) Convex mirror

Statement is correct if the object is placed within 20cm from the lens in the first case and between 20 cm and 40cm in the second case.

Refractive Index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values. 

w = cnv (where n:refractive index,c=speed of light,v:velocity of light in that medium)

Refractive index of one medium in relation to a second medium is given by ratio of speed of light In second medium to speed of light in first medium.

• When an object is placed in F and F₂ of a convex lens, we get inverted, enlarged and real image is formed beyond 2F₂ which is on the other side of the lens. 
• Hence we need to place the object between 20 and 40 cm of the lens. 
• When an object is placed between F and 0 of a convex lens, its enlarged, erect and virtual image is formed beyond FL i.e. on the same side of lens. 
• So for this we need to place the object at a distance less than 20 cm from the lens