Each photosystem consists of molecules of the pigment chlorophyll.

the answer is: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

the answer would be 2, if crossing over doesn’t occur 2 out of 4 of the daughter cells will have that allele.

hope this : )