Scientists have recently discovered a community of bacteria and clams living under an ice shelf in Antarctica. These organisms live under 600 feet of ice, in the absence of sunlight, and in temperatures considered too cold for most living organisms. The location where these organisms live is unusual because

(1) only biotic factors control the size of the populations
(2) bacteria and clams are found in the same area
(3) of the abiotic factors found in their environment
(4) green plants make energy-rich compounds available

Option 3, of the abiotic factors found in their environment

Explanation:

The abiotic factors such as absence of sunlight and extremely cold temperature represents picture of an extreme habitat under an ice shelf in Antarctica.  

The optimum temperature requirements of bacteria for its survival ranges from 10oC to 20oC. In case,  if a bacteria lives in an environment where temperature is less than -5oC or higher than  50oC, then such habitats are considered to be “habitats with extremities”  as special physiological mechanisms are required to maintain the homeostasis and survive.

Likewise absence of sunlight further adds to the extremities of the habitat.

Option 3, is correct

ice cream

explanation: