What commonly prevents hybrids from being viable offspring?

What commonly prevents hybrids from being viable offspring?

• A. Prezygotic isolating mechanisms
• B. Postzygotic isolating mechanisms
• C. Geographical isolation
• D. Behavioural isolation

Answer: (B)

Hybrids can often face viability issues due to postzygotic isolating mechanisms. Once fertilization occurs and a hybrid zygote is formed, these mechanisms can lead to problems that prevent the hybrid from developing into a healthy, fertile adult. Postzygotic barriers include factors like hybrid inviability, where the developing hybrids do not survive to a mature stage, and hybrid sterility, where adults may be born but are not capable of reproducing (as seen in mules, the offspring of a horse and donkey). These barriers happen after fertilization and effectively reduce the chances of successful reproduction between distinct species, despite initial mating and fertilization.

Hybrids can often face viability issues due to postzygotic isolating mechanisms. Once fertilization occurs and a hybrid zygote is formed, these mechanisms can lead to problems that prevent the hybrid from developing into a healthy, fertile adult. Postzygotic barriers include factors like hybrid inviability, where the developing hybrids do not survive to a mature stage, and hybrid sterility, where adults may be born but are not capable of reproducing (as seen in mules, the offspring of a horse and donkey). These barriers happen after fertilization and effectively reduce the chances of successful reproduction between distinct species, despite initial mating and fertilization.