Question

select the part whose main job is to help ribosomes make proteins. rough endoplasmic reticulum smooth endoplasmic reticulum chloroplast golgi

Explanation:

To solve this, we analyze each option:

• Rough endoplasmic reticulum (RER) has ribosomes attached to its surface. These ribosomes synthesize proteins, and the RER helps in the process of protein synthesis by providing a site for ribosomes and aiding in protein modification/transport.
• Smooth endoplasmic reticulum (SER) is involved in lipid synthesis, detoxification, etc., not protein synthesis with ribosomes.
• Chloroplasts are for photosynthesis in plant cells, not protein synthesis assistance.
• Golgi apparatus modifies, sorts, and packages proteins (and lipids) received from the ER, but it doesn't help ribosomes make proteins directly.

So the rough endoplasmic reticulum is the part that helps ribosomes make proteins.

Answer:

rough endoplasmic reticulum