Answer:
D is rhe answer of rhis question.
Explanation:
collection of cells make tissue, collection of tissues form organ, similarly group of organs combine to form a system and when these systems combine it forms a whole body of organism.
The answer is A. Applied forces are the unbalanced forces a person applies to another object to change its velocity or direction or to make it accelerate. When we pull an object towards us, we are increasing it’s velocity, so it’s an applied force.
They all keep our econemy healthy and clean.