Which of the following is an example of commensalism?

a) birds feed off the flies that swarm around the buffalo

b) a rabbit population is the main source of food for a certain fox population

c) in their attempt to obtain nectar from blooms, bees pollinate a population of flowers

d) ticks can attach and live on the blood of bison

A) Birds feed off the flies that swarm around the buffalo  

Commensalism is a relationship between individuals of two species in which in which only one species obtains benefit and another one receives neither harm nor benefit. Birds feed off the flies that swarm around buffalo is an example of commensalism because birds are getting food as flies that swarm around the buffalo. The buffalo is neither harm nor benefited by this act.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.