What kind of change occurs and salt dissolves in water

Which of the following is an example of an environmental change the affected the evolution of life a. volcanic activity b. changes in climate c. mountain building d. all of the above

Astructure that is found in a plant cell and not in an animal cell is a ? central vacuole mitochondrion nucleus ribosome

In natural selection, what is actually “selected? ” a) alleles are directly selected b) genotypes are directly selected c) phenotypes are directly selected d) entire populations are directly selected