How often does oxygen cycle through the atmosphere?
a. about every 1000 years
b. about every 1500 years
c. about every 2000 years
d. about every 2500 years

Jason adds the antibiotic penicillin to a bacterial culture. the bacteria develop genetic modifications in their genome, which gives them resistance to the antibiotic penicillin. what caused this genetic modification?

What are levels of ecology and how can we remember them

Procedure in pregnancy to have access to fetus. what do you call this procedure?