Sand dunes are formed from wind movement. There needs to be a large amount of loose sand in an area with hardly any vegetation, enough wind to move grains of sand and some kind of obstacle to make the blowing sand lose its momentum and settle in a new place.
Answer:
b) It needs a host to reproduce and cannot do it independently.
Explanation:
<span>Oxytocin stimulates dilation of the cervix. As the cervical opening enlarges, this is an example of positive feedback.
This is the answer i got when looking through my books so hope this helped!!</span>