Consider the following statements, and choose the correct one

Options

A. In organisms with external fertilization zygote is formed in the body of the organism
B. Zygote is formed in all sexually reproducing organisms
C. In all aquatic organisms, gametic union takes place in water
D. Parthenogenesis' is the formation of embryo from an unfertilized male gamete

Answer

To solve the question regarding which statement is correct, we will analyze each statement provided in the question step by step.

### Step 1: Analyze the first statement
The first statement claims that "in an organism with external fertilization, zygote is formed in the body of the organism."
- **Analysis**: In external fertilization, both the sperm and egg are released into the external environment (usually water) where fertilization occurs outside the body. Therefore, the zygote is formed outside the organism, making this statement incorrect.

### Step 2: Analyze the second statement
The second statement states that "in all aquatic organisms, gametic union takes place in water."
- **Analysis**: While many aquatic organisms do undergo external fertilization, not all of them do. For example, some amphibians like salamanders utilize internal fertilization. Hence, this statement is also incorrect.

### Step 3: Analyze the third statement
The third statement claims that "pathogenesis is the formation of an embryo from an unfertilized male gamete."
- **Analysis**: Pathogenesis refers to a form of asexual reproduction where an embryo develops from an unfertilized egg, not from a male gamete. Therefore, this statement is incorrect as well.

### Step 4: Analyze the fourth statement
The fourth statement claims that "zygote is formed in all sexually reproducing organisms."
- **Analysis**: This statement is correct. In sexual reproduction, the fusion of male and female gametes leads to the formation of a zygote, which is a universal phenomenon across sexually reproducing organisms.

### Conclusion
After analyzing all the statements, we conclude that the correct statement is: "zygote is formed in all sexually reproducing organisms."

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