Which of the following statements is not true?

Options

A. Life span is the period from birth to the natural death of an organism
B. All small organisms have very short life span
C. Life expectancy is the characteristic of populations
D. Maximum life span is the characteristic of species

Answer

To determine which statement is not true, let's analyze each statement one by one:

1. **Lifespan is a period from birth to natural death of an organism.**
- This statement is true. Lifespan is indeed defined as the duration from the moment an organism is born until it dies naturally.

2. **All organisms, small organisms have very short lifespan.**
- This statement is not true. Lifespan cannot be generalized based solely on the size of an organism. While many small organisms may have shorter lifespans, there are exceptions. For example, some small organisms like certain species of turtles can live for many years. Therefore, it is incorrect to say that all small organisms have very short lifespans.

3. **Life expectancy is a characteristic of population.**
- This statement is true. Life expectancy refers to the average number of years an individual can expect to live based on statistical averages for a population.

4. **Maximum lifespan is a characteristic of species.**
- This statement is true. Maximum lifespan refers to the longest period any member of a species has been known to live, which is indeed a characteristic of that species.

Based on the analysis, the statement that is not true is the second one: "All organisms, small organisms have very short lifespan."

### Summary of the Solution:
- The statement that is not true is: "All organisms, small organisms have very short lifespan."