The biomolecule that cannot act as a chemical messenger [hormone] is
Proteins
Steroids
Fatty acids
Carbohydrates
Carbohydrates cannot act as chemical messengers or hormones. Proteins, steroids, and fatty acids are all examples of biomolecules that can act as hormones or chemical messengers. Proteins can act as hormones, such as insulin and growth hormone, while steroid hormones are derived from cholesterol and include hormones such as testosterone and cortisol. Fatty acids can also act as hormones, such as prostaglandins. Hence, the correct answer is option 4.