Which of the following is true regarding species interbreeding?

• A. Species can always interbreed regardless of separation.
• B. Species are defined by their ability to interbreed successfully.
• C. Species never change over time.
• D. All species can interbreed without restrictions.

Answer: (B)

The statement that species are defined by their ability to interbreed successfully is correct. In biological terms, a species is typically defined as a group of organisms that can breed with one another and produce fertile offspring under natural conditions. This concept is known as the biological species concept. Successful interbreeding is crucial because it facilitates gene flow between individuals, allowing a species to maintain a cohesive genetic identity over time.

Additionally, this ability can help maintain the characteristics that define a species and is a key factor in evolutionary processes. While geographic and reproductive isolation can influence interbreeding, the core definition emphasizes the potential for successful reproduction among individuals within the same species. This understanding is also essential in studying speciation—the process through which new species arise, often as a result of barriers that restrict interbreeding with the populations of their ancestral species.