Answer:
High concentrations of vasoconstrictor substances will increase the peripheral resistance.
Step-by-step explanation:
Vasoconstriction substances cause blood vessels to narrow their lumen. The more narrow lumens, harder it is for the blood to go through that vessel. The reason for this is because the resistance increased, meaning that the friction between the blood and the vessels' walls is higher.
When we talk about peripheral resistance, it means the sum of all individual resistance of the body blood vessels (all arteries, all capillaries, all veins).