Which of theese is an abiotic factor pf an aquarium ecosystems?
a) plants growing from the gravel
b) fish swimmimng in the water
c) algae growing on the grass
d) gravel on the bottom of the aquarium

D) gravel on the bottom of the aquarium. "Abiotic" means "non-living," so you would essentially pick the answer that does not include any organisms (the organisms here are plants, fish, and algae).

Your answer is D.

Abiotic means a nonliving factor of an ecosystem. Reading through all of the answers you can conclude that plants are living, fish are living, and algae are living. However gravel at the bottom of an aquarium is definitely not living, as rocks never are.

Hope this helps! Would love brainliest trying to get to expert, thanks!