Answer:
Scientists believe that the Earth was formed about 4.5 billion years ago. Its early atmosphere was probably formed from the gases given out by volcanoes. ... The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane.
Answer:
If you're a first-time mum, active labour may take about eight hours
Answer:
3rd or 4th one
I don't know the exact sry
Answer:B:they are created when a cell spilts into two copies of itself..
Explanation: