study the four statements (A-D) given below and select the two correct ones out of them
(A) Definition of biological species was given by Ernst Mayr
(B) photoperiod does not affect reproduction in plants
© Binomial nomenclature system was given by R.H Whittaker
(D) In unicellular organisms, reproduction is synonymous with growth
The two correct statments are

Options

A. (ii) and (iii)
B. (iii) and (iv)
C. (i) and (iv)
D. (i) and (ii)

Answer

To determine which two statements are correct from the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement A**: "Definition of biological species was given by Ernst Mayr."
- **Analysis**: This statement is true. Ernst Mayr is known for defining the biological species concept, which describes species as groups of interbreeding natural populations that are reproductively isolated from other such groups.

2. **Statement B**: "Photoperiod does not affect reproduction in plants."
- **Analysis**: This statement is false. Photoperiod, which refers to the duration of light exposure, significantly affects the reproduction of plants by regulating flowering time. Many plants require specific light durations to flower and reproduce.

3. **Statement C**: "Binomial nomenclature system was given by R.H. Whittaker."
- **Analysis**: This statement is also false. The binomial nomenclature system, which is the formal system of naming species, was developed by Carl Linnaeus, not R.H. Whittaker. Whittaker is known for proposing the five-kingdom classification system.

4. **Statement D**: "In unicellular organisms, reproduction is synonymous with growth."
- **Analysis**: This statement is true. In unicellular organisms, such as bacteria, reproduction often occurs through processes like binary fission, which leads to an increase in cell number. Thus, growth (increase in size or number) and reproduction (production of new cells) are essentially the same in this context.

### Conclusion:
The two correct statements are:
- **A**: Definition of biological species was given by Ernst Mayr.
- **D**: In unicellular organisms, reproduction is synonymous with growth.

### Final Answer:
The two correct statements are **A and D**.

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