Answer:
Because Scientists Uses hypothesis and try tests and try proving their points while regular normal people use it to just state a statement
"The uncertainty<span> in </span>velocity<span> is Δv=1.05⋅105m/s . According to the Heisenberg </span>Uncertainty<span> Principle, you cannot measure simultaneously with great precision both the momentum and the position of a particle. m - the mass of an electron - 9.10938⋅10−31kg."
-socratic.com</span>
Hi there!
Although there are only 20 amino acids, these amino acids can combine into an innumerable amount of combinations to form different and unique proteins.
In case that doesn't make sense to you, I'll provide you with an analogy. You could be provided with 20 different LEGO bricks to work with. While there may only be 20 bricks, these bricks can combine into a vast amount of different formations, structures, etc. Amino Acids work in the same way.
Yes, it is true that ions can have a positive or negative charge.