Approximately how long ago did the sun form? 4.5 million years ago 4,000 years ago 4.5 billion years ago none of these are correct

4.5 billion years ago

Explanation:

The sun formed about 4.57 billion (4.567 billion) years ago when a molecular cloud collapsed. Some physical models indicate that the star gets up to 10 percent brighter every billion years, so today's sun is about 40 percent brighter than it was at the time of its creation.

The future of the sun will be marked by the moment when all its hydrogen is converted to helium. When this occurs, it will be increased in size by up to 200 times, and may reach the orbit of Venus.

At the end of its life, the Sun will suffer a huge gravitational collapse, its size will be reduced until it becomes a dwarf white star. Astronomers estimate that at this stage the sun will be about 50 percent of its current mass and that its size will be comparable to that of Earth.

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

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i think the answer is c hope this