Given below are a few statements related to external fertilization. Choose the correct statements.
(i) The male and female gametes are formed and released simultaneously.
(ii) Only a few gametes are released into the medium.
(iii) Water is the medium in a majority of organisms exhibiting external fertilization.
(iv) Offspring formed as a result of external fertilization have better chance of survival than those formed inside an organism.

Options

A. iii and iv
B. I and iii
C. ii and iv
D. I and iv

Answer

To solve the question regarding external fertilization, we will evaluate each statement provided and determine which ones are correct.

### Step-by-Step Solution:

1. **Understanding External Fertilization**:
- External fertilization occurs when the male and female gametes unite outside the female's body. This process is common in aquatic organisms like fish and amphibians.

2. **Evaluating Each Statement**:
- **Statement (i)**: "The male and female gametes are formed and released simultaneously."
- **Evaluation**: This statement is **correct**. In external fertilization, both male and female gametes must be released at the same time to increase the chances of fertilization, as male gametes need to swim to the female gametes in the water.

- **Statement (ii)**: "Only a few gametes are released into the medium."
- **Evaluation**: This statement is **incorrect**. In external fertilization, a large number of gametes are released to enhance the likelihood of fertilization, as many gametes may be lost to predation or environmental factors.

- **Statement (iii)**: "Water is the medium in a majority of organisms exhibiting external fertilization."
- **Evaluation**: This statement is **correct**. Most organisms that undergo external fertilization, such as fish and amphibians, utilize water as the medium for gamete release and fertilization.

- **Statement (iv)**: "Offspring formed as a result of external fertilization have a better chance of survival than those formed inside an organism."
- **Evaluation**: This statement is **incorrect**. Offspring produced through external fertilization generally have a lower chance of survival compared to those that develop inside a protective environment, such as within the mother, due to higher risks from predators and environmental hazards.

3. **Conclusion**:
- The correct statements are (i) and (iii). Therefore, the answer to the question is that statements 1 and 3 are correct.

### Final Answer:
The correct statements related to external fertilization are:
- (i) The male and female gametes are formed and released simultaneously.
- (iii) Water is the medium in a majority of organisms exhibiting external fertilization.