Question

Deep in sea , sunlight can hardly reach ,yet there are plants like brown and red alga found here. How do you think they are able to synthesise their food...?

Answer 1

Sunlight is must for photosynthesis. So deep creatures are not capable of photosynthesis since ,as you mentioned they do not have access to sunlight. But the plants that you have mentioned, red and brown algae are not as deep as you might have guessed. They live in deep areas which receives sunlight to atleast some extend.

They have special adaptations to low light and they also tend to grow slowly. Less photosynthesis means less energy and a slower growth rate.

Basically they absorb green light which most plants don't. They adapt to the mechanism which helps them in performing photosynthesis.