4.6 billion years ago
The study pushes back the clock on the origin of Earth's water by hundreds of millions of years, to around 4.6 billion years ago, when all the worlds of the inner solar system were still forming. Scientists had suspected that our planet formed dry, with high-energy impacts creating a molten surface on the infant Earth.
i hope this helped, have a nice day! (o:
A proposed explanation for a wide range of observations and experimental results that is supported by a wide range of evidence. ... Most factors are held constant in a scientific experiment because you can only change one factor in an experiment so if you notice something, you'll know what caused it.
<span>The word from the pick list that fits here is "enzyme". Enzymes are normally spcialised protein molecules and they act as catalyst ie agents to speed up a reaction in causing traits to develop in the genes of organisms in reaction to chemical stimulants.</span>
