Hormone Identification

The question asks to identify the animal hormone from the given options. Let's analyze each option:

• Cytokinins: These are a class of plant growth hormones that promote cell division and growth. They are primarily found in plants, not animals.
• Insulin: This is a crucial hormone produced by the beta cells of the pancreas in animals (including humans). It regulates glucose metabolism and blood sugar levels.
• Auxin: This is another major class of plant hormones responsible for phototropism, root growth, and other developmental processes.
• Gibberellins: These are plant hormones that stimulate stem elongation, germination, and flowering.

Conclusion on Animal Hormone

Based on the analysis, Cytokinins, Auxin, and Gibberellins are exclusively plant hormones. Insulin is the only hormone listed that is produced and functions in animals.

Therefore, Insulin is the correct answer.