Questions: In living systems, the predominant organic molecules are , which are largely responsible for the structure, behavior, and unique qualities of a cell. polysaccharides nucleic acids

The answer is the second one (or B): nucleic acids.

Explanation for each option:

1. Polysaccharides: These are complex carbohydrates composed of long chains of monosaccharide units. While polysaccharides play important roles in energy storage (e.g., glycogen in animals, starch in plants) and structural support (e.g., cellulose in plants, chitin in arthropods), they are not the primary molecules responsible for the structure, behavior, and unique qualities of a cell.

2. Nucleic acids: These are macromolecules that include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Nucleic acids are crucial for storing and transmitting genetic information, guiding the synthesis of proteins, and regulating cellular activities. They are fundamental to the structure, behavior, and unique qualities of a cell because they determine the cell's genetic blueprint and control the expression of genes.

Summary: The predominant organic molecules in living systems that are largely responsible for the structure, behavior, and unique qualities of a cell are nucleic acids.