Final answer:
The melting temperature of a phospholipid decreases as the length of its fatty acyl chains gets shorter.
Step-by-step explanation:
The melting temperature of a phospholipid decreases as the length of its fatty acyl chains gets shorter. For example, phospholipids with shorter fatty acyl chains, such as those found in dairy products, have lower melting points and are more liquid. This is because shorter chains do not stack together tightly like longer chains, resulting in decreased intermolecular attractions and weaker forces holding the molecules together.