Which of the following is the main function of centrosomes in animal cells?

The threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential.

Most often, the threshold potential is a membrane potential value between –50 and –55 mV.

The membrane potential of a neuron is determined by the distribution of ions across the cell membrane.

At rest, the inside of a neuron is more negative than the outside due to the presence of negatively charged proteins and other molecules.

The movement of ions across the cell membrane can change the membrane potential.

For example, when sodium ions enter the cell, they make the inside of the cell more positive (less negative), causing depolarization.

Choice B is incorrect because -80 mV is below the typical threshold value for mammalian neurons.

Choice C is incorrect because +35 mV is above the typical threshold value for mammalian neurons.

Choice D is incorrect because 0 mV is above the typical threshold value for mammalian neurons.

The polarity of water molecules explains its solvent abilities for certain substances.

Water is a polar molecule because it has a partial positive charge on one end and a partial negative charge on the other end due to the unequal sharing of electrons between the oxygen and hydrogen atoms.

This polarity allows water to dissolve other polar substances and ionic compounds.

Choice A. Kinetic energy of liquid water molecules is not the correct answer because kinetic energy refers to the energy of motion and does not directly explain water’s solvent abilities.

Choice B. High specific heat is not the correct answer because specific heat refers to the amount of heat required to raise the temperature of a substance and does not directly explain water’s solvent abilities.

Choice C. High surface tension is not the correct answer because surface tension refers to the cohesive forces between liquid molecules and does not directly explain water’s solvent abilities.