Peripheral resistance increases with which of the following?

Peripheral resistance is largely influenced by the characteristics of blood vessels and the properties of the blood itself. One of the primary factors contributing to increased peripheral resistance is the length of the blood vessels. As vessel length increases, the surface area in contact with the blood also increases, which creates more friction and resistance to blood flow. Essentially, the longer the vessel, the more resistance there is to the flow of blood through it.

In contrast, decreased blood viscosity would lead to lower resistance, as less viscous blood flows more freely. Similarly, a larger vessel diameter reduces resistance, allowing blood to flow more efficiently, while increased blood temperature typically decreases blood viscosity, further reducing resistance. Thus, greater vessel length is the only correct answer in this context as it directly contributes to an increase in peripheral resistance.