11. Iron is a solid metal, and oxygen is a gas. When iron and oxygen atoms combine, they form a solid called iron oxide.
How should iron oxide be categorized?
A atom
B element
C gas
D molecule

1. isogamy 1 organisms with gametes of the same size and shape 2. anisogamy organisms with gametes of different sizes and shapes 3. oogamy 2 organisms with gametes of the same shape but different sizes 4. gonads gamete-producing organs in lower plants 5. gametangia gamete-producing organs in animals