Which of the following are necessary for evolution by natural selection to take place?
(i) Offspring resemble their parents more than other individuals in the population.
(ii) Differences among individuals exist and lead to different numbers of successful offspring being produced.
(iii) Individuals adjust their development depending on the enviorment
(iv) Every individual possess enormous fertillity.

Options

A. i and ii
B. ii and iv
C. i,iii and iv
D. iii only

Answer

To determine which statements are necessary for evolution by natural selection to occur, we will analyze each of the four statements provided:

### Step-by-Step Solution:

1. **Evaluate Statement (i)**: "Offspring resemble their parents more than other individuals in the population."
- This statement is **incorrect** for natural selection to occur. While it is true that offspring typically resemble their parents, this resemblance does not allow for the introduction of new traits that are essential for evolution. Natural selection requires variation among individuals for new traits to emerge.

2. **Evaluate Statement (ii)**: "Differences among individuals exist and lead to different numbers of successful offspring being produced."
- This statement is **correct**. Variation among individuals is crucial for natural selection. If individuals differ in traits that affect their survival and reproduction, those with advantageous traits will produce more offspring, leading to the evolution of the population over time.

3. **Evaluate Statement (iii)**: "Individuals adjust their development depending on the environment."
- This statement is **correct**. The ability of individuals to adapt to their environment is a key aspect of natural selection. Those that can adjust and survive in changing environments are more likely to reproduce, passing on their advantageous traits to the next generation.

4. **Evaluate Statement (iv)**: "Every individual possesses enormous fertility."
- This statement is **correct**. High fertility rates can lead to a larger number of offspring, which increases the chances of some individuals possessing advantageous traits that will survive and reproduce. However, fertility alone does not guarantee evolution; it must be coupled with variation and adaptation.

### Conclusion:
- The necessary conditions for evolution by natural selection to take place are statements (ii), (iii), and (iv). Statement (i) is not necessary as it does not promote the introduction of new traits.

### Final Answer:
The necessary statements for evolution by natural selection are:
- (ii) Differences among individuals exist and lead to different numbers of successful offspring being produced.
- (iii) Individuals adjust their development depending on the environment.
- (iv) Every individual possesses enormous fertility.