Seaweed belongs to which of earths spheres?

A. Atmosphere

B. biosphere

C. geosphere

D. hydrosphere

The answer is B. biosphere

The correct answer is: B. biosphere

The biosphere or ecosphere is defined as the zone of life on Earth, because it includes all the living organisms on Earth. Biosphere integrates all living beings and their relationships and interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere.

Seaweed is one of the species of marine algae and it includes some types of red, brown, and green macroalgae. So, as a living organism it is the part of biosphere.