How are cells, tissues, and organs related?

Cells are considered the fundamental units of life. The cells in complex multicellular organisms like people are organized into tissues, groups of similar cells that work together on a specific task. ... At each level of organization—cells, tissues, organs, and organ systems—structure is closely related to function.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.