The two events that occur when gravity causes a nebula to collapse into itself are:
A. Nuclear fusion start.
B. A new star forms.
Explanation:
- Nebula are giant clouds of dust and gases.
- These clouds are considered as progenitors of stars and planets.
- The gravitational pull within these giant clouds result these large masses to collapse towards their centre.
- The gravitational collapse results in tremendous rise in temperature till a point where nuclear fusion begin .
- The stars are born out of such mechanism and act as a source of heat and light in universe.
I think the most accepted Theory to make up living things is the cell theory.
The four phases of the menstrual cycle are menstruation, the follicular phase, ovulation, and the luteal phase. Common menstrual problems include heavy or painful periods and premenstrual syndrome (PMS). Knowing when in the menstrual cycle a woman is most likely to conceive can increase the chance of pregnancy.