How do physical conditions change with depth beneath Earth’s surface?

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.

Environmental differences within ecosystems are generally caused by

How does the study of genetic disorders such as pku biologists understand normal alleles?