The answer is Silurian period (443 million to 416 million years ago). This was the era when life in the seas and oceans began to conquer land. This is associated with a period of warm climate, rising sea and ocean levels hence giving shallow-water grounds where reefs developed. Plants like bryophyte began to develop including the emergence of terrestrial arthropods
The correct answer is - C) 667 x 10-13.
The constant that is used in the equation for gravity, or rather gravitational pull, is 0.0000000000667. This same number, in proper scientific notation goes in the shape of 667 x 10-13.
The reason for that is very simple. Any number multiplied with 10-13 will give the exact same number, but as the last part of 13 decimal number. The -13 part dictates the number of decimals. So in the case of 0.0000000000667, the last part 667 is the number that is multiplied, but because the multiplying is in minus, the number goes on the back of the number. Since it has three numbers in it, ten zeros are added in front of it, in order to get the 13 decimals.
Answer:
b. the 20 amino acids found in proteins differ in the composition of their R groups, which may be either polar or charged.
Explanation:
Since the proteins are polymers joined by a big number of amino acids, all the joins occur the same way because in all the amino acids there is always one part that is exactly the same in all of them.
The rest of the molecule in the amino acids, the R group, is different in each one, that is the characteristic of each one, and this is the part that can give the name and some other chemical properties.