How do cells obtain energy, and why is this energy crucial for forming macromolecules?

• A. Cells do not require energy to form macromolecules.
• B. Cells obtain energy solely from sunlight.
• C. Energy is only needed for cellular movement, not for macromolecule synthesis.
• D. Cells obtain energy through processes like photosynthesis and cellular respiration, which is used to synthesize macromolecules like proteins and nucleic acids.

Answer: (D)