21. A population is best described as
- A. A group of the same species of organisms living together
- B. A group of animals and plants living together
- C. A group of insects and grasses
- D. Different species of wild animals
Correct Option: Answer is A
A population is described as the total number of organisms of the same species living together in a given area at a particular time.
22. The number of times an organism occurs within a given area of a habitat is referred to as
- A. Population growth rate
- B. Population frequency
- C. Population growth rate
- D. Population density
Correct Option: Answer is B
Population frequency refers to the number of times an organism occurs within a given area of a habitat
23. Reading the verdict of a case by a magistrate is an example of
- A. A reflex action
- B. An instinct
- C. A conditioned reflex
- D. A voluntary action
Correct Option: Answer is D
A voluntary action is controlled by the cerebrum in the forebrain which is the largest part of the brain
24. Which of the following structures controls the activities of the living cell?
- A. Nucleus
- B. Centrosome
- C. Mitochondrion
- D. Golgi body
Correct Option: Answer is A
Nucleus is a part of living things which controls activities due to the presence of the DNA in it.
25. Which of the following are components of glomerular filtrate?
- A. All the components of blood except mineral salts
- B. Water and salt only
- C. All the components of blood except plasma protein and cells
- D. Blood cells, amino acid, salts and nitrogenous wastes
Correct Option: Answer is C
Glomerular filtrate contains H2O, glucose, salts and urea and it is identical to blood plasma that lacks most proteins.
26. The sum total of adaptive changes from pre-existing form that have taken place over a long time resulting in diversity of forms, structures and functions among organism is referred to as
- A. Specification
- B. Inorganic Evolution
- C. Evolution
- D. Organic Evolution
Correct Option: Answer is D
Organic evolution is the sum total of adaptive changes from pre-existing or old form that have taken place over a long time resulting in diversity of forms, structures and functions among organisms
27. The specific portion of a habitat which is occupied by a particular species is referred to as
- A. Ecological population
- B. Ecological niche
- C. Biotic community
- D. Ecosystem
Correct Option: Answer is B
Ecological niche refers to the specific portion of a habitat which is occupied by a particular species or organism. It is the functional position of an organism within the community
28. In plants, respiration occurs in
- A. The stomata and lenticel only
- B. Mesophyll cells only
- C. All living cells
- D. The root only
Correct Option: Answer is C
Respiration can either be aerobic or anaerobic respiration. Hence, in plants, all living cells take part in a form of respiration. Plant respiration is a rather diffuse process. It occurs all over the plant.
29. Which of the following is an example of discontinous variation?
- A. The range in height of a pea plant from 30cm to 50cm
- B. Offsprings including two male cats and three female cats
- C. The colour of pear plants grown in the dark
- D. The adult body weight ranging from 50kg to 95kg
Correct Option: Answer is B
Discontinuous variation is the differences of variations in behaviour by which organisms can be grouped into 2 or more classes within a population without any intermediates among them e.g Behaviour, ability to roll tongue.
30. Which of the following type of soil has the highest water retaining capacity?
- A. Loam
- B. Laterite
- C. Clay
- D. Sand
Correct Option: Answer is C
Clay soil is the soil with highest water retaining capacity.