Review why carbon can form a variety of organic compounds in a variety of shapes.

Carbon atoms readily bond with each other and can form long chains, branched molecules, and rings—an enormous variety of carbon backbones for organic molecules.

Explanation:

-google

There answer is options 1 and 2.

Explanation:

To test the example given in the question where some ponds have toads with darker colors and some with lighter colors, we can select;

1 - Ponds can be observed for the feeding habits of the predators and this can explain why toads with lighter or darker colors are the majority of the population in some ponds.

2 - The mating preferences of the female toads can be observed and examined statistically which can give us a pattern of preference.

The other options can not be selected as testable hypotheses because of the uncontrollable and subjective variables such as the quality of the food or the toad's genes and the stress of the environment of the pond.

I hope this answer helps.