Correct Answer: D) Axis

Explanation

The correct answer is Axis. The axis articulates with the atlas through the odontoid process.

Correct Answer: C. single cell

Correct Answer: C. All the cells in organism are the same

Correct Answer: D. IV, III, II, I

Correct Answer: D. chlorofluorocarbons

Correct Answer: A. gynoecium

Correct Answer: A. the different groups of plants and animals in the same area and interacting with each other

Correct Answer: B. lymphocytes

Explanation

(a) The principles involved in the following methods of food preservation are:

(i)Salting:- It raises the osmotic concentration of food. and removes water from or dehydrates the food (ex - osmosis) to an intolerable level.

(ii)Refrigeration: It provides lower temperature within the food, retards (slows down) biological processes in spoilage organisms in food and kills some micro-organisms or slows down the activities of spoilage organisms in food.

(iii)Drying: It removes water or moisture and dehydrates food, prevents normal microbial activities which requires water and increases osmotic concentration of food which kills spoilage organism.

(iv)Smoking: It creates or generates high temperature/heat Its carbon kills micro-organisms in food, causes dehydration, increases osmotic pressure and hence, killing of the microbes.

(v)Chemicals: It chokes /suffocates/ spoilage organisms in food, dehydrates/toxicates spoilage organism in food and finally kills organisms.

(b) Problems that may be caused by human over - population are:

(1) Reduction of availability of land for agriculture.

(2) Shortage of food resulting in competition and starvation.

(3) Causes unemployment.

(4) Reduces per capita income/causes poverty.

(5) Causes outbreak of disease / epidemics/ health hazard.

(6) Causes inadequate medical care, social welfare services and shelter.

(7) Leads to increased social vices like crimes, juvenile delinquency, drug abuse e.t.c and aggression.

(8) Causes inadequate educational facilities and other public utility services.

(c) Ways by Which government may increase food production are:

(i) Distribution of high quality seeds and other planting stock which are high - yielding, disease/pest/drought resistant.

(ii) Distribution of fertilizers and other agro - chemicals at subsidized rate to increase crop yield.

(iii) Distribution of tractors/other farm machines/implements for hiring for easy and quicker cultivation of large farm/area of land.

(iv) Providing extension services to local farmers to intimate them with modern farming practices/techniques.

(v) Establishment of river basin authorities which makes water available for irrigation and dry season farming.

(vi) Good roads and stable markets, for easy distribution of products.

(vii) Government should make available storage facility to prevent spoilage.

(viii) Establishment of research institutes to research on food varieties.

(ix) Government should grant agricultural loan to encourage farmers to produce more food.

Explanation

(a) A Cell can be defined as the basic structural and eg. Cool, Wood functional unit of a living organism. Or it could be Volcanoes referred to as the smallest unit of living organism or Diffusion basic unit of life

(b) Structure of DNA:DNA consist Carbon dioxide In of two chains of nucleotides, twisted into each other the atmosphere p n to form a double helix. Each nucleotide is made up Putrefaction of a phosphate group alternating with sugar molecule or deoxyribose, a nitrogenous base or (cytosine, Dead /4 Respiration and deca adenine, guanine, thymine) or purines and y/ Photosynthesis Green manure and plant residue pyrimidines. The nitrogenous base from one chain link up with a compatible base of the opposite chain Dead and or adenine with thymine, guanine with cytosine. The DNA is like a rung of a ladder through a hydrogen teal decay of plants Plants bond. Absorption through roots

(c) Description of the process of mitosis:Mitosis occurs. in somatic cells or body cells or meristematic cells. Inorganic salts of carbonates In soil At the beginning of mitosis or prophase nuclear membrane and nucleolus disappear. Chromosomes Losses in form of carbonates become more visible, the chromosomes replicate. of metals like calcium and potassium They are normally made up of two strands or chomatids, spindles are formed. Chromosomes are then arranged at the equator or middle of the cell or ) metaphase. The chromosomes attach themselves at the centromere to the spindle and chromatids separate at the centromere. Each member of the pair move to the opposite pole of the cell or anaphase. The two sets of chromatid grouped together at the opposite pole and become less visible or Telophase . The nuclear membrane reappears including the nucleolus. The cytoplasm constrict in animals cells to form daughter cells. In plant cells, wall is formed between two sets of chromatids. Then two daughter cells are formed.

(d) Importance of mitosis to living organisms:

(1) Mitosis helps in the growth or development.

(2) It assist in Repair of cells

(3) It also ensures exact copy of DNA or sum total of inherited factors or transmission of genes to the daughter cells or ensures consistency of DNA. )