Gravity , Explosion
<u>Explanation:</u>
Nebulae are made of dust and gases—mostly hydrogen and helium. The dust and gases in a nebula are very spread out, but gravity can slowly begin to pull together clumps of dust and gas. As these clumps get bigger and bigger, their gravity gets stronger and stronger.
Eventually, the clump of dust and gas gets so big that it collapses from its own gravity. The collapse causes the material at the center of the cloud to heat up-and this hot core is the beginning of a star.
Answer:
Wild forest fires cause extensive damage to flora and fauna and result in the destruction of man-made property in and around the area of the fire. To maintain the health of the forest and prevent the large wild forest people or man]nagers use prescribe fire or controlled fired when there is no risk of loss of life and resources.
These controlled fires are used by forest officials and fire managers to prevent or keep wildfires at bay. It helps in cleared-off areas by playing the role of a barrier for fire from spreading further.
There is always the risk of flora fauna and the life of wild animals. They can get killed and lose their habitat and the smoke rose from this fire causes for environmental concern too.
