C.
Biotic mean alive, so we can cut off the first 2 easily. Aquatic birds eat frogs, so that one is safe for now. A decrease in something parasitic usually helps the population, so D is out too. The only one left is C.
Answer:
chitin
Explanation:
chitin is a complex carbohydrates, similar to cellulose, that makes up organic structure, such as the cell walls of fungi and exoskeletons of insects and other arthropods.
Answer:
I think it's called 'filling in'
Explanation
Hope this helps :)
The body has levels of organization that build on each other. Cells make up tissues, tissues make up organs, and organs make up organ systems. The function of an organ system depends on the integrated activity of its organs. For instance, digestive system organs cooperate to process food.
