What difference between heterozygous and homozygous?

Which statements correspond to cellular respiration? co2 diffuses passively into the cell. co2 diffuses passively out of the cell. co2 must be pumped out of the cell. o2 diffuses passively when produced inside the cell. o2 diffuses passively when converted to co2. o2 is pumped in and forces co2 out.

Which element is found in both dna and proteins

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these