Two pink-flowering plants are crossed. the offspring percentages are 25% red, 25% white and 50% pink. what would the parent's genotypes be?
a. both homozygous dominant
b. both homozygous recessive
c. both heterozygous
d. one homozygous dominant, one homozygous recessive

When red crosses with white flowers to give pink flowers, we are looking at incomplete dominance, i.e. the offspring is a blend (pink) of the parents' characteristics (red or white).

Since we're given in the question two pink flowers crossed to give 25% red, 25% whit and 50% pink, we would be thinking of a punnett square between RW and RW, to give

RR RW

RW WW

Since both parents are RW, that makes both parents heterozygous.

they deliver oxygen to the blood

the answer is trees if i'm not mistaken