Hi there!
A prezygotic isolating mechanism is a mechanism that causes something to happen, not allowing the organisms to breed before fertilization. I'll explain each one for you.
A - That is postzygotic because the organisms were not stopped before fertilization. The result is a sterile organism.
B - Again, that is postzygotic because the organism was produced.
C - This is prezygotic! The sperm dying shows that something is in action to prevent fertilization, meaning that it cannot happen.
D - Fertilization was successful, so it is postzygotic.
ANSWER:
C - the sperm dies when it reaches the female tract
If you need help with any more problems, feel free to message me and I'd be more than happy to help you work through them and provide explanations.
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!
Some mutations have a positive effect on the organism in which they occur. They are called beneficial mutations. ... They increase an organism's changes of surviving or reproducing, so they are likely to become more common over time. There are several well-known examples of beneficial mutations.
A solar eclipse occurs<span> when the moon gets between Earth and the sun, and the moon casts a shadow over Earth. </span>A solar eclipse<span> can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface.</span>
