Answer :
Amino acids join by forming (1) peptide bonds. Water is released.
The chains of amino acids vary according to their (2) side chains, which each have differing makeup.
These chains determine the protein’s structure and they fold to create a unique (3) third-dimensional shape.
Explanation :
Amino acid : The amino acids are the building blocks of protein. Amino acids are the compound which consist both amine 
and carboxylic 
groups along with the side chains. In the protein, many amino acids are linked by the peptide bonds.
Th peptide bonds are formed by the combining of amino group of one amino acid to the carboxylic group of another amino acid by releasing of water.
Some examples of amino acids are glycine, lysine, alanine, etc.
Peptide bond formation image is shown below.
In the image 'R' can be contained by different groups like hydrogen, methyl, phenyl, etc
The environment affects natural selection. Speices need to adapt to changes in environmnet. The weaker organisms which fail to adapt to environment perish while the stronger ones who adapt to the environment survive. This is how environment affects natural selection.
D. Has a uniform composition and is only able to be separated by chemical means.
Answer:
A water molecule consists of three atoms; an oxygen atom and two hydrogen atoms, which are bond together like little magnets. The atoms consist of matter that has a nucleus in the centre. one mole of water contains 6.02 x 1023 MOLECULES of water But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 1024 atoms in a mole of water.Feb 12, 2003
Explanation:
