In which major weather events of the 20th century did climate play a significant role?
a. mt. saint helens eruption
b. space shuttle challenger disaster
c. dust bowl
d. sinking of the titanic

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 impacts on evolution : mastery test

Witch theory suggests all living things are made up of cell or cells