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The answer is (D) immature and living

Lysosomes: They are single- membrane small vesicular structures, found in the cytoplasm of all eukaryotic cells, except mammalian RBC’s. They contain enzymes and are formed by Golgi apparatus. 

Functions: They are involved in intracellular digestion of foreign food or microbes and are also involved in autolysis or self-digestion of cells, after their death. 

Peroxisomes: They are found in photosynthetic cells of plants, liver and kidney cells of the vertebrates and contain two types of oxidative enzymes: oxidase and catalase, bounded by a unit membrane. 

Functions: These are involved in the removal of toxic substances, by oxidative reactions. In plant cells, these also help in photorespiration. 

Centrosome: A centrosome is a light microscopic organelle, formed of two dark, coloured granules called centrioles, surrounded by a transparent cytoplasmic area called centrosphere. It lies near the nucleus and is commonly called the call centre. 

Functions: Centrosome helps in cell division, in animal cells. They also help in the formation of cilia and flagella of the cells.

The answer is (A) Blue-green algae.

The answer is (C) Hyaloplasm

A tracheid is a single cell, whereas trachea or vessels are tube-like bodies, formed by rows of cells.

The answer is (A) food

The answer is (A) Robert Brown

(a) Cell wall provides rigidity, structural strength and definite shape to the cell. 

(b) It helps in transport of various substances across it.

The answer is (B) Collenchyma

Blood is a fluid connective tissue. In blood, the cells move in a fluid matrix called blood plasma. The cells in blood are different from the other connective tissue cells, both in structure and functions. Blood plasma is a straw coloured, slightly alkaline fluid. Blood plasma contains cells called blood corpuscles and blood platelets. Blood cells are of two types-Erythrocytes and Leucocytes. Blood circulates within the blood vessels throughout the body and thus, connect every part of the body.

Collenchyma is the chief mechanical supporting tissue in plants.

Main functions of areolar tissue are as follows: 

(i) These tissues fill the space inside the organs. 

(ii) It provides support, elasticity and strength to the body parts. 

(iii) Aerolar tissue binds different tissues together, e.g., the skin with underlying parts, blood vessels and neurons to other body parts. 

(iv) It helps in repair of tissues and healing of wounds. 

(v) It helps in fighting foreign antigens and toxins.

Meristematic tissue functions to produce new cells, which keeps on differentiating to form specialised cells.

Leeuwenhoek saw the living cell for the first time.

The largest cell of the human body is Neuron (nerve cell)

Cell organelles which perform specific functions for the cell are enclosed by membranes. But, viruses do not have any membrane. So viruses do not show any characteristics of life on its own. Outside its host cell, a virus is completely inert. They become active only when they enter in some living body and uses its cell machinery.

Prokaryotic Cell: 

(i) Size of the cell is generally small (1-10 m). 

(ii) The nuclear region is poorly defined, due to the absence of nuclear membrane, known as a nucleoid. 

(iii) It contains a single chromosome. 

(iv) The nucleolus is absent. 

(v) Membrane-bound cell organelles are absent. 

Eukaryotic Cell: 

(i) Size of the cell is generally large (50 – 100 m)

(ii) The nuclear region is well-defined and surrounded by a nuclear membrane. 

(iii) It contains more than one chromosome. 

(iv) The nucleolus is present. 

(v) Cell organelles such as mitochondria, plastids, endoplasmic reticulum, golgi apparatus, lysosomes, peroxisomes, etc. are present

Proteins are synthesized in the ribosomes.

Cell Division: The German biologist Walter Flemming was the first, who observe the process of cell division, and gave it the term mitosis. A cell division is a process by which a single cell multiplies in number. A growing cell undergoes interphase (a period of non-apparent division) and the period of division. In interphase, cell doubles in size and chromosomes duplicate. Therefore, cell division can be considered a process of ensuring exact duplication of cellular information and its equal distribution to the two daughter cells. Thus, the two type of cell divisions observed, are mitosis and meiosis.

Two unicellular organisms are: 

(a) Amoeba 

(b) Chlamydomonas

Cellulose and Pectin are deposited on the cell wall of collenchyma tissue.

Chromosomes are located in the nucleus of plant and animal cells. They are composed of DNA and protein. Chromatin material is entangled mass of thread-like structures. Chromatin material gets organised into chromosomes, just before the cell divides.

Mitochondria have their own DNA and ribosomes. Therefore, they are able to make their own proteins.

The process of gene exchange takes place in the prophase I of meiosis. In the beginning of prophase I, chromosomes appear as long thread like structure and show bead-like thickenings at regular intervals. The homologous chromosomes form pairs. This phenomenon of chromosomal pairing is called synapsis of the chromosomes. The paired chromosomes are identical, one coming from the father, through his sperm and the other from mother, through her ovum. Pairing is remarkably exact and specific. It takes place to point to point. The two homologues do not fuse during pairing but remain separated. The paired chromosomes become short and thick and contain four chromatids. 

Each chromatid at this stage has its own centromere, resulting in four centromeres. These chromatids are called sister chromatids. Now, two of the chromatids (one paternal and one maternal) of the homologous, exchange segments. The process is called crossing over.

The objective of amitosis in bacteria is to increase progeny and propagation of generation. 

Amitosis: The nuclear material containing a circular chromosome, elongates. A constriction develops in the middle portion of a chromosome. When constriction increases the circular chromosome, it divides into two halves. In the beginning, the chromosome is attached to the cell wall. But as the cell increases in size, the two halves of chromosome separate. After that, the constriction develops into the cell wall. When constriction increases, the bacterial cell divides into two daughter cells.

The study of temperature of the ocean is essential because-

1. The temperature of the ocean provides information on the global climate system. 

2. It is also important for the study of marine ecosystems. 

3. The temperature of the ocean water is responsible for the movement in the oceanic water. 

4. Rising temperatures cause coral bleaching and loss of breeding grounds for marine fishes and mammals. 

5. The study of temperature of the ocean can help in establishing marine protected areas and forming precautionary limits to prevent overfishing, protecting ocean ecosystems and shield humans from the effects of ocean warming.

Correct Answer is  (d) Palk

The division of the cytoplasm occurs after the Karyokinesis, and differs in animal cells and plant cells: 

(i) In animal cells: Towards the end of telophase, a peripheral furrow appears in the cytoplasm, precisely in the middle of the cell. The furrow deepens, and gradually reaches the centre, dividing the cell into two daughter cells. 

(ii) In plant cells: After the karyokinesis, small membrane-bound vesicles settle in the form of a row in the middle of the cytoplasm. The vesicles fuse to form a cell plate. The latter changes to middle lamella on either side, of which is the deposited material for the cell wall. 

The formation of cell wall divides the cell into two: 

Plant Cell: 

(i) No centriole present 

(ii) No aster forms 

(iii) Cell plate forms 

(iv) No furrowing of cytoplasm at cytokinesis 

(v) Occurs mainly at meristems. 

Animal Cell: 

(i) Centrioles present 

(ii) Asters form 

(iii) No cell plate forms 

(iv) Furrowing of cytoplasm at cytokinesis, 

(v) Occurs in tissues, throughout the body.

A unicellular organism has a single cell carrying out all life process. This is unable to exhibit a wide range of different functions and easily susceptible to damage, that can lead to the death of the organism. 

For example: Amoeba, Chlamydomonas etc. A multicellular organism has different cells carrying out different functions. They are more efficient and carries out no. of activities. They have a greater capacity of survival and they are continuously replaced. 

For example: Cat, Dot, Human being etc.

Mitochondria: They are small bodies that occur in large numbers.

 A mitochondrion consists of: 

1. an outer membrane 

2. an inner membrane 

3. inner membrane folded inwards to form the cristae. 

4. The cristae lie in a ground substance called as a matrix. 

Functions of Mitochondria: 

1. It generates energy for various activities of the cell. 

2. Whenever the cell requires energy, ATP molecule breaks down generating energy to be used by the body, in order to make chemical compounds and perform mechanical work. 

3. Mitochondria have their own DNA and ribosomes hence, are able to make some of their own proteins.

Meiosis is an indirect type of cell division, which occurs at the time of gamete formation. It involves two successive divisions, rapidly occurring one after the other and results in the formation of four daughter cells, with half the number of chromosomes as compared to the parent cell. Such cells are called haploid cells (n), whereas parent cells are diploid (2 n). The 1st division of meiosis reduce the chromosomal number to half and is, therefore, called the reductional division. It produces two haploid cells from the parent diploid cell. The Ilnd division of meiosis is similar to mitosis, as the chromosomal number of the haploid cells produced in the reductional division above, remains unchanged. Four haploid cells result at the end of meiosis.

1. Mid-oceanic ridges are submerged mountain ranges that separate deep portion of the sea (Ocean) floor. 

2. The Indian Ocean has a Mid Ocean ridge called as a Mid Indian Oceanic Ridge. 

3. It originates from the Gulf of Eden near the Peninsula of Somalia.

4. It further extends toward the south and on the eastern side of Madagascar, it divides into two branches. 

5. One branch diverts towards southwest and extends up to Prince Edward Island. It is known as Southwest Indian Ocean Ridge. 

6. The second branch extends south eastwards up to Amsterdam and St. Paul Island. It is known as Mid Indian Ocean Ridge. 

7. Mid Indian Oceanic Ridge has many parallel ridges. This ridge is not continuous due to many fracture Zones in it. e.g. Owen Fracture Zone. Amsterdam Fracture Zone, etc.

Monsoon climate has developed in the Indian sub-continent because-

1. The Indian Ocean spreads between Africa in the west, Asia in the north and east, Australia in the east and Southern Ocean in the south. 

2. The Indian Ocean does not extend northwards to the Arctic Ocean like the Atlantic Ocean and the Pacific Ocean.

3. This has resulted in complete blockage of the Indian Ocean towards its north. 

4. This peculiar arrangement of the ocean and the continental portion contributes a lot to the development of the monsoon climate of the Indian subcontinent. 

5. During summer solstice, sun shines vertically on tropic of cancer, so there is summer season over the Indian subcontinent. 

6. Due to continuous heating, low pressure area is created, moisture laden south west monsoon winds give rainfall on the Indian sub-continent, that is rainy season. 

7. During winter solstice, due to slanting sunrays, the temperature goes down, that is winter season. 

8. Thus, there is monsoon climate with three distinctive seasons.

(c) Both A and R are correct and R is the correct explanation of A.

The answer is (B) By the presence of cell wall

Cell theory: A cell is the smallest structural and functional unit of any living organism. The concept that the cell is the basic unit of life is called the cell theory. At first, German Scientist, M.J.Schleiden and Theodor Schwann established cell theory. The cell theory was further expanded by Virchow, by expressing that all cells arise from pre-existing cells. 

Thus the modern version of the cell theory summarized as follows: 

1. All living things, whether plants or animals are composed of cells and their products. 

2. A cell is the smallest unit of structure and function, which arise from preexisting cells and their continuity is maintained through the genetic material. 

3. All cells are basically alike, found after chemical analysis and studying the functions of different components. 

Following are the concepts of the modern cell theory: 

1. The body of each living being is composed of one or more cells and cell products. 

2. The cell is the fundamental unit of all biochemical reactions. 

3. A cell is also a hereditary unit because it contains genetic material in it. 

4. New cells are formed from the division of pre-existing cells. 

5. All organisms start life from a single cell. 

6. All organisms function through the activities of cells.

(c) Both A and R are correct and R is the correct explanation of A.

Correct Answer is  (d) Madagascar

Correct option is (b) biosynthesis of 3-LAA

The answer is (A) cells are fundamental structural units of plants and animals

(d) Both A and R are correct but R is not the correct explanation of A.

D) All the above

The answer is (D) Ribosome

Correct option is  (a) high

Correct option is B) Osmosis

Correct Answer is  (d) Bundle

Correct Answer is  (a) Maldives