Why is the photosynthesis equation often written with several arrows ?

Because of its structure the cell membrane is known as a phospholipid ? a. bilayer b. molecule c. fluid d. barrier

Which represents the cross between parent plants if one is heterozygous for yellow-colored pods and the other is homozygous for green-colored pods? yy  ´    ´    ´    ´  yy

How much time has elapsed from the very beginning of "the memior of the conquistador bernal diaz del castillo" to the end? a. castillo's whole life b. a quarter of an hour c. a few weeks d. a decade