A study was completed to determine the effect of the banded tetra on other plant and animal populations in its tropical stream environment. The scientists looked at the population level of other species before and after they removed banded tetras. What MUST be TRUE about the banded tetra?

A

The banded tetra is a keystone species.

B

The banded tetra is a foundation species.

C

The banded tetra is in a parasitic relationship with these other populations.

D

The banded tetra is in a mutualistic relationship with these other populations.