The respiratory system is responsible for the exchange of oxygen with what gas?

a) nitrogen

b) hydrogen

c) water vapor

d) carbon dioxide

Which best explains why viruses do not have special structures or enzymes that allow them to make their own food? viruses can use energy in living cells that they infect. viruses can replicate inside a host that they infect. viruses can cause contagious illnesses in host cells. viruses integrate their rna or dna into infected cells.

Compare the composition of the moon's surface with the composition of the earth's surface.

Why was mendel's work not accepted at the time? o a. his results were false. o b. he did not repeat his experiments. o c. he did not have any data. o d. his results were surprising,