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.

That is true tge cactus as a structural adaptation to its envirinment has it leaves reduced to spines. but this doesnt mean it cant produce food it produces food because of the presence of chlorophyll in its stem