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!
I'm pretty sure the answer is B
Organic materials less than "50,000 years" old are the type of materials that scientists would date with the carbon-14 method.
False this could only happen if the pathologist or anthropologist was there at the time of death
Answer:
K+
Explanation:
Leak channels are the gated channels that randomly open and close. The plasma membranes have many more potassium ion (K+) leak channels than the leak channels for other ions such as sodium ion. Also, the potassium ion leak channels are leakier than the sodium leak channels and allow exit of more and more K+ from the neurons. This makes the inside the neuron negative at rest and outside becomes more positive. In this way, the leakage of K+ across the K+ leak channels is mainly responsible for maintaining the resting potential.
