The four main categories of large biological molecules present in living systems are
a. rna, dna, proteins, and carbohydrates
b. monosaccharides, lipids, polysaccharides, and proteins
c. nucleic acids, carbohydrates, monosaccharides, and proteins
d. proteins, nucleic acids, carbohydrates, and lipids
e. proteins, dna, rna, and steroids

D. Proteins, Nucleic Acids, Carbohydrates, and Lipids

Explanation: Living systems have important macromolecules that act as structural blocks or participate in metabolism.

Proteins. These macromolecules are composed by aminoacids and can be structural like collagen, act as enzymes as oxidases, act as a receptors as tyrosin kinase receptors, among other functions.Nucleic acids. These macromolecules are composed by nucleotides and acts a inheritance molecules: DNA and RNA.Carbohydrates. These macromolecules are composed by monosaccharides and can be structural as cellulose or participate in metabolism like glycogen and glucose.Lipids. These macromolecules are composed by carbon, hydrogen and oxygen atoms. Participate in metabolism as energy reserve and structural in biological membranes.

The truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey