The primary functions of blood include which of the following?

• A. Regulating digestion only
• B. Transport, protect, and regulate
• C. Producing enzymes for digestion
• D. Filtering waste only

Answer: (B)

Blood’s main work centers on transport, protection, and regulation. It moves oxygen, carbon dioxide, nutrients, hormones, and wastes throughout the body, delivering what tissues need and carrying away what they don’t. It protects us with immune cells and antibodies that fend off infections, and with platelets and clotting factors that help stop bleeding after injury. It also helps regulate body temperature, pH, and fluid balance by distributing heat and by maintaining stable chemical conditions in the tissues.

Enzymes for digestion aren’t produced by blood; that’s the job of digestive organs like the pancreas and stomach. Filtering waste is important, but blood’s role isn’t only to filter—its broader transport and regulatory functions are essential for maintaining homeostasis.