Correct Answer: D) Charles Darwin

Explanation

The theory of natural selection in evolution was formulated by a scientist called Charles Darwin. The theory explains that species of organisms can change over time through the process of evolution. In this process, traits that are helpful for survival and reproduction become more common in a population, while traits that are harmful become less common. This results in the gradual development of new species from existing ones. It is important to note that there were other scientists who contributed to the understanding of evolution, but Darwin's theory of natural selection is considered to be one of the most significant and widely accepted explanations of how evolution occurs. Therefore, the correct answer to the question is option D: Charles Darwin.

Correct Answer: B. in water and on moist land

Correct Answer: D. maintenance of osmotic balance

Explanation

a. Importance of the following in the Nitrogen Cycle

(i) Lightning

- When lightning occurs, nitrogen reacts with oxygen in air to form nitrous oxide/oxides of nitrogen;

- which is further oxidised to form nitrogen (IV) oxide /nitrogen dioxide;

- which dissolves in rain water to form nitric and nitrous acids;

- (that fall to the ground) when it reaches the soil combines with bases/mineral salts to form nitrates;

- which the plants absorbs.

(ii) Nitrosomonas

- Is a nitrifying bacterium in the soil;

- that converts ammonia to nitrites in the soil.

(iii) Azotobacter

- Is a nitrogen-fixing bacterium in the soil;

- that converts nitrogen in the soil;

- into ammonium compounds/amino compounds and protein in the soil;

- converts nitrites to nitrates in the soil.

b. Excretory organs

Insects – malpighian tubules;

Earthworm – nephridium

c. Explanation of diseases

(i) Hepatitis

- Is the inflammation/destruction of liver cells;

- hepatitis can arise from bacteria/virus/an autoimmune disease;

- or from excess consumption of alcohol.

The symptoms include fatigue;

- loss of appetite/anorexia;

- muscle aches/pains;

- flu;

- fever;

- nausea;

- jaundice;

- and dark coloured urine/stool.

(ii) Kidney stones

- Are small solids/crystals of concentrated minerals/uric acid found in the urine;

- they are formed if there is an excessive loss of water/insufficient water intake;

- so that the solubility of minerals/calcium phosphate/calcium oxalate in the urine is reduced;

- high levels of uric acids/amino acids can lead to kidney stones;

- bacteria may be trapped in the kidney tubules as the kidney stones get bigger;

- symptoms are sharp pain at the flank of back;

- frequent urination;

- nausea;

- sweating;

- kidney stones can be treated by medications;

- change in diet of food rich in calcium;

- surgery;

- drinking plenty of water.

d. (i) Effects of lack of sense receptors in the skin

- Humans will not be able to sense/feel/perceive external stimuli in the environment;

- pain;

- touch;

- a change in temperature;

- pressure;

- danger which could lead to death.

(ii) Layers of the epidermis

- cornified layer/stratum corneum;

- granular layer/stratum granulosum;

- malpighian layer/stratum Malpighi.

e. (i) Metamorphosis

Is the development of some/certain organisms from the egg; to an adult stage; involving three to four stages.

(ii) Type of metamorphosis of listed insects

Correct Answer: C. Taraba state

Correct Answer: D. competition

Correct Answer: B. survival of the fittest

Correct Answer: C. xerophytes

Explanation

(a)(i) Diseases of plants caused by bacteria are:

(i) Soft roots

(ii) fire blight, wilts, crown gall. Disease of animals caused by bacteria are tuberculosis, cholera, leprosy , gonorrhoea, syphilis, diptheria, tetanus

(ii) Ways in which bacteria are useful are:

(1) Some bacteria are used in the preparation of cheese, butter and vinegar.

(2) Some are used in the production of antibiotics, enzymes, vitamins and amino acids for commercial purposes.

(3) In leguminous plants, bacteria such as Rhizobium found in the root nodules convert atmospheric nitrogen to soil nitrogen thus enhancing the nitrogen content of the soil.

(4) Some bacteria help in the digestion of cellulose

(5) Some bacteria help in the fermentation of alcohol and beverages.

(6) Certain bacteria known as sewage bacteria assist in the decomposition of sewage into harmless substances that could be used as manure.

(b) Mosquitoes can be controlled in the following ways:

(1) Bush around the surrounding should be cleared to prevent breeding grounds for mosquitoes.

(2) Mosquito net should be provided or fitted to our windows to prevent mosquitoes from coming within to suck human blood.

(3) Apply insecticides to kill mosquito or pour kerosine or oil on stagnant water around the house to prevent breeding.

(c)Aim: To show the presence of bacteria under the finger nails.

Apparatus: Incubator, innoculating loop, nail cutter, petridish, blood agar, microscope and cover slip.

Procedure: Cut the finger nails and place them in a petridish which have the blood agar. Then incubate at 37°C for two days.

Observation: It was discovered that colonies of bacteria were growing on the blood agar. On gram staining, one saw clusters of cocci bacteria.Conclusion: The growth of cocci bacteria indicates that bacteria grow on finger nails.

Correct Answer: D. Rhizopus