Which phrase best describes a biome?

a community and its abiotic features
an interacting community of different species
a group of individuals of the same species
a large area dominated by specific kinds of organisms

You are working in the lab and are working with the same element but with varying isotopes of the element. you are working with c-11, c-13, c-14, and c-15. what is the average atomic mass of this element? (use periodic table) a- 12 b-15 c-14 d-13