Answer - C. Reproduction
Reasoning - This was answered before within the community. Here's a reasoning why I chose the answer. - Just like a hydra they are abundant since they can reproduce asexually without having to reproduce with a mate, which means they the ecosystem can eat they and keep the active food chains going.
Based on the question above, the best answer would be:
That the headless horseman had to hold his head in his arms
is because he “wanted to see what’s ahead.”
Or a simple geometric equation of SOH CAH TOA would help
solve the angle degree.
The action or fact of forming a united state that seems as the best answer