Organ level of organization in living things is found in?

Step 1: Analyze the question The question asks which option shows the organ level of organization. Living things are organized in this order:

Cell → Tissue → Organ → Organ system → Organism

Step 2: Explain the concept

• Cell level: a single cell that performs its own functions (e.g., spermatozoon, red blood cell).
• Tissue level: a group of similar cells doing the same job (e.g., muscle tissue).
• Organ level: different tissues working together to perform a specific function (e.g., kidney, heart, leaf, stomach).
• Organ system level: several organs working together (e.g., the excretory system).
• Organism level: a complete living individual.

Step 3: Go through the options

• A. Waterleaf plant: This is a whole organism, so it is at the organism level, not the organ level.
• B. Virus particle: A virus is not cellular. It is just genetic material in a protein coat and does not show the levels of organization.
• C. Kidney: This is an organ made of different tissues (epithelial, connective, and so on) that work together to filter blood and form urine. This fits the organ level.
• D. Spermatozoon: This is a single specialized cell, so it is at the cell level.

Step 4: Answer The kidney is the only option that is an organ.

Tip: Remember the sequence "C-T-O-S-O" (Cell, Tissue, Organ, System, Organism). When you see a named body part like the heart, kidney, liver, or leaf, think "organ." A single cell is cell level, and a whole plant or animal is organism level.