1.In some cases humans may consume other animals as food. Sponges are not a good option. Why do you think they are inedible?

Sponges are made of material that is, first of all, hard to eat. Second of all, sponges don't provide many nutrients that would make eating the sponge worth it in the first place

littering streams           is the answer

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".