Question

Many of the ancient phototrophic and heterotrophic bacteria lived in colonial associations known as

Answer 1

a.stalagtites
b.stalagmites
c.stromatolites
d.none of the above

Answer 2

Stalagtites and stalagmites aren't biological features at all, they're rock formations found in caves. What's the likelihood that a phototrophic (something that gets its energy from the sun) is going to be living in a deep, dark cave?