The nitrogen cycle could not exist without bacteria. Bacteria that lived inside the ground, catch the ntirogen that has been fixed and convert it into nitrate. This nitrate than used as a nutrients during photosynthesis from which the plants produce another fixed nitrogen and completed the cycle.
The skull is not fully put together. It is made of cartilage. That is why babies have a soft spot.
Infant suckling
<span>Infant suckling is the stimulus that is needed
for continued and sustained production of breast milk. When an infant suckles, stimuli
are transmitted to the mother's pituitary gland and prolactin (a hormone
responsible for milk production) is released by the pituitary and this leads to
the production of more milk. The more an infant suckles, the higher the
prolactin level and the amount of milk produced.</span>
I believe it is D, all of these. :) I hope this helps! Please tell me if I'm wrong :)
