Ageing is characterised by

Options

A. Decline in metabolic activity
B. Increase anabolism
C. Increase catabolism
D. Increase catabolism

Answer

### Step-by-Step Solution:

1. **Understanding Aging**: Aging is the final stage of life, following the juvenile and reproductive stages. It is characterized by various physiological changes.

2. **Metabolic Activity**: One of the primary characteristics of aging is a decrease in metabolic activity. This means that the body's processes that convert food into energy and manage bodily functions slow down.

3. **Hormonal Changes**: The decrease in metabolic activity is largely due to a reduction in hormone levels. Hormones play a crucial role in regulating metabolism, and as individuals age, the production of certain hormones declines.

4. **Comparison of Stages**: In the juvenile phase, there is growth and an increase in metabolic activity due to rising hormone levels. During the reproductive stage, metabolic activity is maintained due to the presence of reproductive hormones. However, in the senescence phase, the decline in hormone levels leads to decreased metabolic activity.

5. **Conclusion**: Therefore, the correct characterization of aging is a decrease in metabolic activity due to a reduction in hormone levels.

### Final Answer:
Aging is characterized by a decrease in metabolic activity due to a decrease in the amount of hormones.

---