I believe the answer is A. The R group gives amino acid unique characteristics. Hope this helps :)
The changes in environment can cause the raising of the sea level, which can push animals further inward, which in turn destroy habit, as they began to get clumped together vegetation begins to go away, thus resulting in less species, also hotter climate makes sure that animals with very heavy coats of fur, die out pretty quickly if not cooled (over heating)<span />
C. acidic because anything with a pH of less than 7 is acidic
A is the correct answer! :)
The correct answer is c. Heterotrophs compete for the same food source.
As it can be seen from the image of the food web, the tree or plants which are autotrophs are consumed by various heterotrophs. Autotrophs provide as a source of food for several heterotrophs but several heterotrophs depend on other heterotrophs such as smaller insects or animals for their food. As shown in the food web, both frog and lizard are consumers of insects so both being heterotrophs are competing for the same source of food which is insect here.