Which of the following terms is used to define the cyclic period of sexual receptivity in mammals?

• A. Metamorphosis
• B. Homeostasis
• C. Apoptosis
• D. Estrus

Answer: (D)

Verified step by step guidance

1. Understand the question: The problem asks for the term that defines the cyclic period of sexual receptivity in mammals. This is a biological concept related to reproduction.
2. Review the provided options: Metamorphosis, Homeostasis, Apoptosis, and Estrus. Each term has a distinct biological meaning, so we need to identify the one related to sexual receptivity.
3. Define each term: Metamorphosis refers to the developmental transformation in organisms (e.g., caterpillar to butterfly). Homeostasis is the maintenance of stable internal conditions in an organism. Apoptosis is programmed cell death. Estrus is the period of sexual receptivity in female mammals, often associated with hormonal changes and ovulation.
4. Focus on relevance: Among the options, Estrus is the only term directly related to the cyclic period of sexual receptivity in mammals. The other terms are unrelated to reproduction or sexual receptivity.
5. Conclude: Based on the definitions and relevance, Estrus is the correct term for the cyclic period of sexual receptivity in mammals.