The embryo refers to an undeveloped animal or plant. true or false

If a polyatomic ionic compound has gained two hydrogen ions, then how does its name begin?

Can someone me with 3 and 4 plz. this is for masteries test.

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth