23. When does extinction occur?

A. when the population of a species begins declining rapidly

B. when the population of a specie has become so low

C. when the last member of that species dies

D. when the population of a specie becomes unstable

24. One of the major causes of extinction nowadays is?

A. habitat destruction & hunting C. overharvesting & poaching

B. taking animals for profit & overpopulation D. diseases, inability to adapt

25. Arrange the following steps of photosynthetic process according to how it occurs.

I. absorption of light

II. electron transport leading to the reduction of NADP+

to NADPH

III. generation of ATP

IV. conversion of CO2 into carbohydrates (carbon fixation)



A. I, II, III, IV C. III, II, I, IV

B. II, I, III, IV D. IV, III, II, I

26. In which organelle of the internal leaf does the food-making process take place?

A. mitochondria of the plant cell
C. chloroplast of the plant cell

B. spongy mesophyll of the plant cell
D. thylakoid in the stroma
​