The Living World

The correct option is (C) : Interbreeding

A collection of creatures that may effectively interbreed to create viable offspring is referred to as a species. Therefore, regardless of environment, they are not reproductively separated. An organism's ecological niche describes its place in the ecosystem. There is no niche that is shared by two people. If they did, they would be vying for every resource, and the one who was more prepared to fill that niche would seemingly be able to kill the other. Every creature adapts to its surroundings in a unique fashion, with varying demands, interactions, and tolerance levels for various environments.

Species are considered as real basic units of classification.

In biology, among the major taxa in the taxonomic hierarchy, a species is one of the basic units of biological classification. A species is defined as the largest group of organisms capable of interbreeding and producing fertile offspring. As they share more common characters, they form the lowest basic unit of classification. The species have a real existence making the most suitable answers amongst the provided options.

Also Read: Diversity in Living Organisms

Answer: Option 3 - A and D

Explanation:

Let's break down the statements:

(A) Definition of biological species was given by Ernst Mayr:

Correct. Ernst Mayr proposed the biological species concept, which defines species as groups of interbreeding natural populations that are reproductively isolated from other such groups.

(B) Photoperiod does not affect reproduction in plants:

Incorrect. Photoperiod is a critical environmental factor that affects the reproductive behavior of many plants. Plants are classified based on their response to the length of day and night, such as long-day plants (LDP), short-day plants (SDP), and day-neutral plants. Photoperiod has a significant role in the timing of flowering and reproduction.

(C) Binomial nomenclature system was given by R.H. Whittaker:

Incorrect. Binomial nomenclature, the system of giving species a two-part Latin name (genus and species), was established by Carl Linnaeus. R.H. Whittaker contributed to the five-kingdom classification system, not binomial nomenclature.

(D) In unicellular organisms, reproduction is synonymous with growth:

Correct. In unicellular organisms, such as bacteria, reproduction (by binary fission) is often considered synonymous with growth, as the organism divides and multiplies into two identical cells, resulting in an increase in population size.

Conclusion:

The two correct statements are (A) and (D), which makes Option 3 the correct answer.