Please help me! I need to get this one correct!! Which is a biotic component of a marine ecosystem?

a) Phytoplankton on the surface of the ocean
b) The oxygen concentration of the water
c) Rocks on the ocean floor
d) The temperature of the water

Explanation:

Organisms and their immediate environment, with which they interact, together constitute the ecosystem. The various factors that affect an ecosystem can be divided into 2 classes: biotic factors and abiotic factors. The biotic factors include all the living organisms in the ecosystem, while the abiotic factors include the non-living factors.

A

Explanation:

In a marine ecosystem, some of the biotic factor are algae, fungi, microorganisms (such as bacteria), plants, animals and corals. These living beings compete against each other for food and resources, are part of the predator-prey relation, and also include the decomposers.

Biotic components are living organisms in an ecosystem. A biotic factor is a living organism that affects another organism in its ecosystem. Examples include plants and animals that the organism consumes as food, and animals that consume the organism

answer; /// i believe the correct answer is (reactants);