The function of ribosome is

Step 1: Analyze the question The question asks about the main function of the ribosome, a cell organelle.

Step 2: Explain the concept Ribosomes are tiny structures found either free in the cytoplasm or attached to the rough endoplasmic reticulum. They are made of ribosomal RNA (rRNA) and protein. Their job is to read the instructions carried by messenger RNA (mRNA) and join amino acids together in the correct order to build proteins. This process is called translation.

Step 3: Go through the options

• A. Excretion of waste: This is carried out by organs such as the kidneys, and at the cell level by processes like diffusion and by contractile vacuoles in some organisms. It is not a ribosome function.
• B. Protein synthesis: Correct. Ribosomes are the site where proteins are assembled.
• C. Reproduction: Cell division is controlled by the nucleus and the centrioles, not by ribosomes.
• D. Respiration: This takes place in the mitochondria.
• E. Secretion of hormones: This is done by glands and, in the cell, involves the Golgi apparatus. Some hormones are proteins that ribosomes help make, but secretion itself is not the ribosome's function.

Step 4: Answer The function of the ribosome is protein synthesis, which is option B.

Tip: Match each organelle to its job:

• Ribosome → Recipe for proteins (protein synthesis)
• Mitochondrion → respiration (powerhouse)
• Nucleus → control center
• Golgi body → packaging and secretion
• Chloroplast → photosynthesis