Answer:
a. A macromolecule composed of a "string" of subunits stands both for DNA as well as proteins. Both are the macromolecules (large molecule) made of their respective subunits ( DNA made of polynucleotides and Proteins made of amino acids) and contains the stretch of monomers in their structure.
b. Double-stranded stands for DNA as DNA is a double stranded molecule contains two nucleotide chains runs with anti parallel polarity. The one strain has polarity in 5' to 3' direction and other strand has polarity in 3' to 5' direction.
c. Four different subunits stands for DNA. DNA contains the four nitrogenous bases adenine, guanine, thymine and cytosine. These four different nitrogenous bases with deoxyribose sugar and phosphate group may be responsible for the four different subunits of DNA.
d. 20 different subunits stands for proteins. 20 different standard amino acids are known for the formation of proteins. These 20 different amino acids makes the subunits.
e. Composed of amino acids stands for proteins. Proteins are the polymers of the amino acids. Amino acid contain the amine group, carboxylic acid group, hydrogen and R hydrocarbon chain.
f. Composed of nucleotides stands for DNA. DNA are the polymers of nucleotides. The nucleotide contains nitrogenous base, pentose sugar and the phosphate group.
g. Contains a code used to generate other macromolecules stands for DNA. DNA contains nitrogenous bases in the form of codes to generate RNA as well as protein.
h. Performs chemical reactions stands for proteins. Enzymes are made of protein that are responsible for the metabolic and enzymatic reactions of the body.