Mixotrophes! because they are autotrophes and heterotrophes in one :)
A) A metal forms a + charged ion, so D2+
B) A nonmetal forms a - charged ion, so A-
C) C2-
D) B+
D. Oxygen and metal
They usually contain some form of metallic cation, given that carbonates are the most distributed minerals in the Earth's crust.
Hope this helped!
Answer: What are you asking??