Babies, especially those who are at least 4-6 months old, have the tendency to explore objects by touching and holding them, and putting them in their mouth. By this time, it is very important to keep small objects out of their reach so that accidents can be prevented.
Global warming
The increase of greenhouse gases result into global warming :)
I believe that the best answer for this question is "gene mutations." Gene mutations can either take place through nucleotide substitutions, which occur when the the sequence of nucleotides are altered. Frameshift mutations can also occur. They involve the insertion or deletion of a DNA molecule's bases. Hope this helps.
Many theories can never be proven.
Here are a few examples:
-- The moon orbits the Earth.
-- Gravity pulls all masses toward each other.
-- The Earth orbits the sun.
-- Everything is made of atoms and molecules.
-- Atoms are made of protons, neutrons, and electrons.
-- Electrons moving through a wire make electric current.
-- The center of the Earth is molten iron and nickel.
-- The source of the sun's energy is nuclear fusion in its core.
-- Almost all galaxies are moving away from us.
-- The universe is expanding.
None of these statements can be proven. That's why they're not called
Facts or Laws.
It also tells you that some pretty powerful stuff has been done with concepts
that can't be proven. If you want to make an idea look foolish, that doesn't
happen when you say "it's only a theory".