Plant cells have plastids, cell wall, large and permanent vacuoles whereas animal cells don't
The correct answer is compound
13.8 billion years ago
This relic radiation is known as the cosmic microwave background radiation. The chemistry of life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the universe was only 10–17 million years old.
Explanation:
Speed depends on your referential. Some chemical reactions can take only a fraction of a second while others take days.
Combustion is typically very fast. You can also try and look at lithium+water which is a dangerous, fast and exothermic reaction.
