Questions

Gene flow means migration of genes from one to another. This gene flow is caused by individuals moving into population.

The process which wherein an Ecosystem may renew itself is known as Ecological Succession.

The time scale may be decades or a million of years after a mass extinction. 

It may be achieve over a period of time.

Trypanosoma is a protozoan animal. It lives as a parasite in the blood and later invades the cerebrospinal fluid to cause the sleeping sickness. This parasite is transmitted by the Tsetse fly.

United State Library of Congress, Washington D.C.

394  is the code to unlock the key.

If you take the second statement, 7 is incorrect from the first statement and 1 is incorrect from the fourth statement. Hence 4 is correct, but not on the second place. From the third statement, 4 is not on the first place. Hence 4 is on the third place.

From the fifth statement either 6 or 9 is correct. But combining it with the third statement, 6 is incorrect. Hence along with the first statement, 9 is correct and on the second place.

From the third statement, 3 is correct and on the remaining first place.