Which of these is an abiotic factor of an aquarium ecosystem?
a.
algae growing on the glass
b.
gravel on the bottom of the aquarium
c.
plants growing from the gravel
d.
fish swimming in the water

B. Gravel on the bottom of the aquarium

abiotics are non living

Earth's Spheres. Everything in Earth's system can be placed into one of four major subsystems: land, water, living things, or air. These four subsystems are called "spheres." Specifically, they are the "lithosphere" (land), "hydrosphere" (water), "biosphere" (living things), and "atmosphere" (air)

Explanation: