lichens are usually the first organisms to appear in barren, rocky areas the soil shows in time 2 was formed mainly by

 E.) The population of snakes will increase because of decreased predation by eagles.

A food chain is a linear sequence of transfer of food and energy, when one organism is consumed by another organism in an ecosystem. The energy is distributed among various trophic levels of the food chain. The organisms in the higher trophic levels consume organisms in the lower trophic levels.  

In the given situation, the decline in the eagle population due to human activities and pollution will increase the population of the organisms lying in the lower trophic levels such as stock and snakes which the eagle used to obtain as a source of food.