Question

1. Plants in floodplains often get covered by water during floods. Some plants survive the floods because they can continue photosynthesis underwater. However, the plants’ rates of photosynthesis are much lower underwater than above water.Which of the following helps to explain why the rates of photosynthesis are lower underwater than above water?

A. There is too much oxygen in the water
B. There is no carbon dioxide in the water.
C. The chloroplasts do not function underwater.
D. The available light is less intense underwater

Answer 1

The answer is; D

As the sunlight changes media from the atmosphere into the water, some of it is reflected back while the rest is refracted and diffused by the water. The deeper the water column the higher the diffusion. Therefore, leaves under water receive lower sunlight intensity hence slowing down the rate of photosynthesis.