I think the first one is right !.... but the for the other one it's B .
6. Lion
7.raccoon
8.rat
9. A keystone is a organism that helps define the entire ecosystem, and if the species were to disappear from the ecosystem no other species would be able to fill its ecological niche the ecosystem would be forced to radically change allowing new and possibly invasive species to populate the habitat.
The answer will be B. It is common sense
False, atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes
