Hormones because if you think about it. Vertebrates must have backbones and mammals have them. And, humans are basically mammals. And the glands secrete hormones.
A phospholipid is a lipid made of a phosphate group with two fatty acids.
A second messenger is a molecule inside cells that acts to transmit signals from a receptor to a target.
Hoped this helped.
~Bob Ross®
Answer:
Phosphate group is the structural difference between triglycerides and phospholipids. A triglyceride contains three fatty acids attached to the glycerol backbone whereas a phospholipid has two fatty acids and a phosphate group attached to the glycerol.
Explanation:
<span>the study of living organisms, divided into many specialized
fields that cover their morphology, physiology, anatomy, behavior,
origin, and distribution.</span>