Have you finished this?? I need gelp
Answer:
These reactions are collectively called the urea cycle or the Krebs-Henseleit cycle. Ammonia is a toxic product of nitrogen metabolism which should be removed from our body. The urea cycle or ornithine cycle converts excess ammonia into urea in the mitochondria of liver cells.
A sperm and egg combine to make a zygote. (or fertilized egg)
So, the answer would be "A".
I hope this helps!
~cupcake