<span>The use of genetically altered livestock, such as cows, goats, pigs, and chickens, to produce medically useful products is referred to as pharming. The correct option among all the options that are given in the question is the fourth option or the last option. I hope that the answer has come to your help.</span>
They gives us oxygen, they store carbon for us, and they provide materials for tools and shelter for us.
The answer is option D "test the effect of cyanide on algae." Ecologist are researchers who study how organisms interact with their environment so in this case they are testing how algae reacts to cyanide. In another example they will be testing how a ape reacts to having a different fruit tree in their habitat. It wouldn't be option A, B, and C because you have to remember the job of a ecologist and the options are not jobs of one.
Hope this helps.
