Answer:
The Sun and the planets were born from a cloud of gas and dust called the solar nebula 4.6 billion years ago. The collapse of the solar nebula was most likely triggered by a shock wave from a nearby supernova explosion. The Sun formed in the center, with the planets surrounding it in a thin disk.
Explanation:
So they can tell what exact species it is.
Answer:
The same genes or slightly different versions of the same gene can be found on each chromosome in a pair. They form a line and split off bits of themselves, which they barter with one another. In sexual reproduction, crossing over is the first method that genes are shuffled to develop genetic variation.
This I believe would be double covalent bonds
I believe it was John Newlands.
Hope that helped