Question

ipsps (inhibitory postsynaptic potentials)
are local depolarizations.
increase membrane permeability to sodium ions.
block the efflux of potassium ions.
block the efflux of calcium ions.
are local hyperpolarizations.

Explanation:

Inhibitory postsynaptic potentials (IPSPs) are changes in the membrane potential of a postsynaptic neuron that make it less likely to fire an action potential. They are local hyperpolarizations. Depolarizations (as in the first option) make a neuron more likely to fire (like excitatory postsynaptic potentials - EPSPs). Increasing permeability to sodium ions (second option) is associated with depolarization (as sodium influx causes depolarization in many cells). Blocking potassium efflux (third option) would prevent repolarization (since potassium efflux is a key part of repolarization in action potentials). Calcium ion efflux blocking (fourth option) is not the main mechanism of IPSPs. IPSPs typically involve opening of chloride channels (chloride influx) or potassium channels (potassium efflux, which hyperpolarizes the cell as potassium is positively charged and moving out makes the inside more negative) leading to local hyperpolarization.

Answer:

are local hyperpolarizations.