Answer:
4.5 billion years ago
Earth hasn't always been a blue and green oasis of life in an otherwise inhospitable solar system. During our planet's first 50 million years, around 4.5 billion years ago, its surface was a hellscape of magma oceans, bubbling and belching with heat from Earth's interior.
Explanation:
The menstrual cycle is regulated by two hormones secreted from the pituitarygland, follicle stimulating hormone (FSH<span>) and luteinizing hormone (LH).</span>
A. It generally releases more heat than nuclear fission.
Crossing over. Parts of sister chromatids will sometimes switch places with the parallel part, resulting in a completely unique DNA sequence.