Biological rhythms that are repeated once every 24 hours are

Options

A. Circannual rhythms
B. Circadian rhythms
C. Lunar periodicity
D. 1 and 2

Answer

To solve the question "Biological rhythms that are repeated once every 24 hours are," we can follow these steps:

### Step-by-Step Solution:

1. **Understand Biological Rhythms**:
- Biological rhythms refer to the natural cycles of physiological processes in living organisms. These rhythms can be influenced by environmental factors and are regulated by an internal biological clock.

2. **Identify the Types of Biological Rhythms**:
- There are various types of biological rhythms, including circadian rhythms, ultradian rhythms, infradian rhythms, and seasonal rhythms. Each of these has a different periodicity.

3. **Define Circadian Rhythms**:
- Circadian rhythms are specifically those biological rhythms that repeat approximately every 24 hours. They can affect various bodily functions such as sleep-wake cycles, hormone release, body temperature, and other physiological processes.

4. **Evaluate the Options**:
- The question may provide multiple-choice options. For example:
- A) Solcannual rhythms (annual cycles)
- B) Circadian rhythms (24-hour cycles)
- C) Lunar periodicity (monthly cycles)
- From these options, we need to identify which rhythm corresponds to a 24-hour cycle.

5. **Select the Correct Answer**:
- Among the options, circadian rhythms are the only ones that fit the description of biological rhythms that are repeated once every 24 hours.

### Final Answer:
The biological rhythms that are repeated once every 24 hours are **circadian rhythms**.

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