Nan experiment, suppose that the wings of fruit flies were clipped short for fifty generations. the fifty-first generation emerged with normal-length wings. this observation would tend to disprove the idea that evolution is based on
a. inheritance of natural variations
b. inheritance of acquired characteristics
c. natural selection
d. survival of the fittest

b. inheritance of acquired characteristics

Explanation:

For fifty generations wings of fruit flies were clipped. Hence they acquired this trait in their lifetime and not genetically. If acquired characteristics were capable of passing on to next generation, 50 generations would have been enough to inculcate this clipped wing trait in fruit flies. Despite it, the fifty-first generation did not have clipped wings. Hence evolution can not occur without genetic variation. A character simply acquired in lifetime does not create a difference in germ cells and hence is not enough to be passed on to next generation or cause evolution.

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.