Question

select the part whose main job is to send instructions to different parts of the cell. ribosome mitochondria nucleus cytoplasm

Explanation:

The nucleus contains the cell's genetic material (DNA). DNA has the instructions for making proteins and regulating cell activities. It sends these instructions (via mRNA) to different parts of the cell. Ribosomes are for protein synthesis. Mitochondria are the power - houses (produce ATP). Cytoplasm is the fluid where cell organelles are suspended.

Answer:

nucleus