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Leaves of plants helps in excretion in many ways. Excess of water in plants is excreted by transpiration and guttation, that takes place through leaves. Carbon dioxide and oxygen that can be considered as waste products of respiration and photosynthesis respectively are excreted through stomata present on leaves.

(a) Carbon dioxide.

(b) Oxygen.

• Plants give out oxygen during photosynthesis by diffusion which is useful to human beings for respiration.
• Some waste materials of plants for example, gum, resin, latex of rubber, etc. are useful to humans.

• Leaves plays an important role in excretion in plants because CO₂ is expelled out through pores of stomata present in the leaf.
• Plants shed leaves to get rid of excretory products deposited on them.

A is glucose and B is starch.

(i) Plants use different methods to perform excretion. They produce mainly two gaseous waste products, namely oxygen (produced during photosynthesis) and carbon dioxide (produced during respiration). The leaves of plants possess tiny pores called stomata and stems possess lenticels through which O₂ and CO₂ are diffused out of the plant body. 

(ii) Apart from oxygen, plants produce a number of waste products such as excess water, essential oils, aromatic oils, tannins, resins, gums, organic acids, latex, etc. Almost all of these products are useful to human. 

Gums and resins are used for varnishes and adhesives. Essential oils are used in cosmetics and soap making.

(a) Plants obtain food by a process called photosynthesis. 

(b) Plants need nitrogen to make proteins and other compounds. They take up nitrogen from the soil in the form of inorganic salts called nitrates (or nitrites), or in the form of organic compounds which are produced by bacteria from the atmospheric nitrogen.

(a)  Photosynthesis.

(b)  Heterotrophs.

(c)  Autotrophs.

(d)  Chloroplast.

(e)  Guard cells.

(f)  Pepsin.

Photosynthesis reaction: CO₂ + H₂O → C₆H₁₂O₆ + O₂ + H₂O 

Balanced equation: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O 

Step 1: Write the unbalanced equation 

CO₂ + H₂O → C₆H₁₂O₆ + O₂ + H₂O 

Step 2: Compare the number of atoms of reactants with the number of atoms of products. 

Step 3: Now, first we consider the element having unequal no. of atoms on both sides. Thus, first let us consider carbon atom. If we multiply 6 in the reactant (in CO₂), we will get the equal number of atoms as in product (in C₆H₁₂O₆)

Step 4: Write the resulting equation:

6CO₂ + H₂O → C₆H₁₂O₆ + O₂ + H₂O 

Step 5: Now check whether the equation is balanced or not by comparing the atoms

(a) X is sunlight energy and Y is chemical energy. 

(b) 

The photosynthesis takes place in the following three steps; 

(i) Absorption of sunlight energy by chlorophyll. 

(ii) Conversion of light energy into chemical energy and splitting of water into hydrogen and oxygen by light energy. 

(iii) Reduction of carbon dioxide by hydrogen to form carbohydrates like glucose by utilising the chemical energy

Autotrophs are producers that make their own food by the process of photosynthesis. The necessary conditions for autotrophic nutrition, i.e., to make food are the presence of chlorophyll, carbon dioxide, water and sunlight. Glucose produced during photosynthesis is converted to starch and stored as food. 

The by-products of photosynthesis are oxygen and water.

(a) The criteria to decide whether something is alive is the movement. 

(b) The basic functions performed by living organisms to maintain their life on this earth are called life processes. The basic life processes common to all living organisms are ? Nutrition and Respiration; Transport and Excretion; Control and Coordination; Growth; Movement and Reproduction.

(a) Herbivores eat only plants so they need a longer small intestine to allow the cellulose present in the plants to be digested completely. 

(b) If mucus is not secreted, hydrochloric acid will cause the erosion of inner lining of stomach leading to the formation of ulcers in the stomach. 

(c) The contraction and expansion movements of oesophagus also called peristaltic movements pushes the food down into the elementary canal.

(a) The opening and closing of stomatal pores is controlled by the guard cells, when water flows into the guard cells, they swell, become curved and cause the pore to open whereas when the guard cells lose water, they shrink, become straight and close the stomatal pore. 

(b) Plant kept in continuous light will live longer because it will be able to produce oxygen required for its respiration by the process of photosynthesis.

In autotrophic nutrition, organisms obtain their food from inorganic substances. In heterotrophic nutrition, organisms derive their food from organic substances.

The answer is (c) starch

Glycogen is the stored energy in animals, Plants stores energy in the form of Starch.

(a) Autotrophs are those organisms which can make their own food from carbon dioxide and water. Example: Green Plants.

(b) The conditions necessary for autotrophic nutrition are sunlight, chlorophyll, carbon dioxide and water.

The answer is (c) They convert carbon dioxide and water into carbohydrates in the absence of sunlight.

They need sunlight to convert carbon dioxide and water into carbohydrates

Plants get inorganic substances like nitrogen, phosphorus, magnesium, manganese, sodium etc. from the soil. Soil is the nearest and richest source of these elements.

Carbon dioxide and Water.

1. d. Heterotrophic nutrition

2.d. All of the bove

3.a. Humans

4.a. Saprotrophic or parasitic

5.b. Mushroom

Saprotrophic.

Saprotrophic.

(a)  Saprophyte – Saprophytes are the organisms which obtain their food from dead plants (like rotten leaves), dead and decaying animal bodies, and other decaying organic matter (like rotten bread).Example: Fungi and some bacteria. 

(b)  Parasite: A parasite is an organism (plant or animal) which feeds on another living organism called its host.Example: Plasmodium and round worm.

Photosynthesis.

(i)  Saprophytic nutrition: It is that nutrition in which an organism obtains its food from dead organic matter of dead plants, dead animals and rotten bread. Example: Fungi and many bacteria obtain food by saprophytic nutrition. 

(ii)  Parasitic nutrition: It is that nutrition in which an organism derives its food from the body of another living organism (called its host) without killing it.Example: Plasmodium and round worms obtain food by parasitic nutrition. 

(iii)  Holozoic nutrition: It is that nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion; the ingested food is digested and then absorbed into the body cells of the organism.Example: Human beings obtain food by holozoic nutrition.

Saprophytic – Fungi.Parasitic – Plasmodium.Holozoic – Human Beings.

(1) The fatty acids are components of the lipids. When lipids are digested, it forms fatty acids and alcohol (glycerol).

(2) There are certain chemical bonds between fatty acids and alcohol.

(3) Fatty acids are very essential for the health.

(4) After digestion, fatty acids are absorbed into the blood and transported to the cells.

(5) Different types of cells produce their own substances from these fatty acids.

E.g. (a) Plasma membrane is produced from phospholipids.

(b) Hormones like testosterone, progesterone, estrogen, aldosterone are produced from fatty acids.

(c) The axonal coverings around the neurons are also made from fatty acids.

Correct option is: (b) Gibberellin

1. Newtron.

2. Glomerulus.

3. Synapse.

4. Neurons.

5. Ventricles.

6. Central Canal.

7. Filum terminale.

Pituitary gland secretes FSH and LH. LH is known as ICSH in males, as its function in the male body is different. From the gonads of male and female, hormones are secreted which are essential for male and female reproductive functions respectively. These hormones are testosterone secreted from testis in males and estrogen and progesterone secreted from the ovaries in females. Testosterone is essential for masculinity as well as for sperm production while female hormones are essential for changes in the female body leading to motherhood.

Breathing: Breathing refers to the process of taking outer oxygen-rich air inside and exhaling inner carbon dioxide rich air outside or we can say it is the process of exchange of gases. 

The rate of breathing increases during vigorous exercise because during vigorous exercise our body consumes more amounts of energy and our body needs more amount of oxygen and need to remove CO₂. So, in order to fulfill this requirement of the body breathing rate increases during vigorous exercise.

Chemical co-ordination in humans :

• In humans chemical co-ordination is brought about with the help of certain chemical substances called hormones. 
• Hormones are secreted by endocrine glands. These glands are also called ductless glands. 
• These glands do not have any arrangement of their own to either store or carry their secretions. So, the hormones are directly released into the blood circulation. 
• Though the endocrine glands are present at specific locations in our body, their secretions reach all parts of the body via the blood. 
• Endocrine glands along with the nervous systems are responsible for control and coordination in our body. These two systems help each other to control and integrate the various activities of the body.
• A marked difference between these two systems is that nerve impulses are fast but short-lived whereas the actions of hormones are very slow but long-lasting.
• It is very important that hormones are secreted only in the required quantity and there is a special mechanism which controls the quantity and timing of hormone secretion.
• For example, whenever there is an increase in blood glucose level, certain cells in the pancreas get stimulated and as a response, they release a greater quantity of insulin, thus bringing down the sugar level to normal.

• Several different organ systems function in multicellular organisms.
• Their life goes on smoothly if there is coordination between different organ systems or organs and the stimuli in the surrounding.
• Depending upon this, we can say that systematic regulation of different processes can be called control and bringing about the different processes in the proper sequence is called co-ordination.
• If any activity in the body is to be completed successfully, proper co-ordination between different systems, and organs participating at different steps of that activity is necessary.
• If due to lack of co-ordination, there is confusion at any step, the activity may not get completed. There should be no randomness at any step.
• There should be proper co-ordination between internal activities of the body resulting from various factors like body temperature, water- level, enzyme-level, etc. or stimuli arising in the surrounding environment.
• Proper co-ordination between various systems of an organism helps to maintain a state of equilibrium called homeostasis which is necessary for the optimal efficiency of the body.

Correctly matched column:

Correct option is: (b) cerebellum

Correct option is: (a) control of voluntary movements

Correct option is: (d) Medulla oblongata

Breathing in Humans has two processes 

1) Inhalation 

2) Exhalation 

Inhalation: 

• Inhalation is the process of taking oxygen. During this process, ribs come out and diaphragm moves down.
• This increases the volume of the lungs and decreases the pressure.
• This will make the air move towards the lungs.

Exhalation: 

• Exhalation is a process of throwing out carbon-dioxide. 
• During this process, ribs go down and diaphragm moves up. 
• This decreases the volume of the lungs and increases the pressure. 
• As a result air moves out of the lungs.

The process of removal of toxic waste from the body of an organism is called excretion. The excretory unit of a kidney is called nephron.

The process of removal of toxic waste from the body of an organism is called excretion. The excretory unit of a kidney is called nephron.

(a) Respiration is a vital function of the body as it provides energy for carrying out all the life processes which are necessary to keep the organism alive. 

(b) 

Aerobic respiration 

(i) Aerobic respiration takes place in the presence of oxygen. 

(ii) Complete breakdown of food occurs in aerobic respiration. 

(iii) The end products in aerobic respiration are carbon dioxide and water. 

(iv) Aerobic respiration produces a considerable amount of energy. 

Example: Human Beings. 

Anaerobic respiration 

(i) Anaerobic respiration takes place in the absence of oxygen. 

(ii) Partial breakdown of food occurs in anaerobic respiration. 

(iii) The end products in anaerobic respiration are ethanol and carbon dioxide (in yeast) and lactic acid (in animal muscles). 

(iv) Much less energy is produced in anaerobic respiration. 

Example: Yeast. 

(c) 

(i) Anaerobic respiration. 

(ii) Aerobic respiration.

All organisms perform many activities such as growth, reproduction, movement, etc. to perform all these activities of the body we need energy and this energy comes from food we eat after digestion the food is brought to the cell where is broken into carbon dioxide and water to release energy and this process is called respiration all the organisms respire to get energy so respiration is a vital function of body.

OR

The food material taken in during nutrition is used in cells to provide energy for various life processes. This energy is released during the process of respiration. The oxygen taken in during respiration is transported to cells for carrying out oxidation of food. This energy is stored in the form of ATP, which is used for the entire working of the body. Also, the CO₂ released during respiration has to be removed immediately out of the body.

So without respiration, the body will not get any energy to function in any way. Hence it is a vital function or process of the body.

Precautions are :

(i) Ensure that the experimental set-up is air-tight.

(ii) KOH is corrosive. Handle it carefully.

i. Lipids are molecules formed of fatty acids and glycerol (alcohol) which have specific bonds between them.

ii. When excess of fats are eaten, they are stored in adipose connective tissue.

iii. Progesterone, estrogen and testosterone are the reproductive hormones produced from fatty acids.

iv. The digested fats are absorbed in the form of fatty acids. These are converted back to phospholipids from which plasma membrane of cells is formed.

v. After complete digestion of lipids they are converted to fatty acids and glycerol. 1 gm of lipid provides 9 kcal of energy.

The chart shows process of energy production through aerobic respiration of carbohydrates, proteins and fats.

(Answers to the blanks in chart are given in bold.)

• Gustatory nerves are concerned with sense of taste whereas olfactory nerves are concerned with the sense of smell.
• Gustatory nerves are found in the tongue from where they carry impulses to the gustatory cortex in the brain.
• Whereas the olfactory nerves are found in the nasal passage from where they carry impulses to the olfactory lobes in the brain.