Answer:
D
Step-by-step explanation:
Cells make up tissues. So, they have a relationship. (A) is wrong.
Random cells do not combine together. Instead, cells are grouped and assigned specific tasks. Those specific cells make up specific tissues. (B) is wrong.
Cells are the fundamental units. Tissues are not. Also, different organisms have different organ systems with unique functions, hence cells and tissues are different. (C) is wrong.
Cells specified for certain tasks come together to form tissues. (D) is correct.