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.
The natural disasters branch of earthe science. The
Answer: National park service
Explanation:
Answer is C A 20kg object
Two factors contributed to the success of the pteridophytes: the extreme miniaturization of the gametophytic generation and an important development of the sporophytic generation (development of the tree forms).
Pteridophytes are a group of plants that peaked in the Carboniferous (-300 million years). It is the first great terrestrial plant civilization. These plants would have appeared in the Devonian -400 million years ago, perhaps from certain primitive terrestrial plants which, unlike bryophytes, would have favored the diploid generation on the haploid generation.
Particularly well adapted to terrestrial life, they have created, thanks to the development of tree forms, immense forests whose fossilization is at the origin of coal deposits.
Pteridophytes are at the origin of an evolutionary lineage based on the extreme miniaturization of gametophytic generation and an important development of sporophytic generation, leading to all tracheophytes including current flowering plants. Pteridophytes are well adapted to terrestrial life, however fertilization still requires the presence of water since male gametes are swimmers.
