C. Shield Volcano.. think of Hawaiian volcanoes,they are basaltic eruptions, very effusive and unexplosive and are characterised by slow lava movement and very little tephra from the eruption. The basalt erupted is very hard, dense rock and so can be built up easily.
The number 45 means that the subject has 44 normal autosomal chromosomes (22 chromosomes pairs) plus one (1) good sex chromosome (out of the normal homologous pair). The X0 means that the subject, usually a female, lacks one sister chromosome of the homologous X chromosome pair, or has a partial X sister chromosome.
First, we can eliminate 2 options. The simple unit of protein is amino acid, instead, the simple unit of fat and lipids are fatty acids and glycerol, therfore we can eliminate option A and D because fatty acids does not exist in protein.
Now we are left with B and C. To solve that, we need to understand that protein is made of a chain of amino acids, a lot of amino acids are chemically combined and cannot be broken down unless the use of enzymes. Amino acid are actually the monomers that forms protein.
Therefore, the answer is C. amino acid combine to form a protein chain.