Why do we need to breath air instead of

Mainly because our lungs are made to intake air, and if we where to inhale water we would drown. oxygen can only be obtained from the air because our lungs would be able to expell the excess stuff from air easier than in water. hope i helped.

Myelinated axons utilize fewer voltage-gated channels than unmyelinated axons of the same length and diameter.

Myelinated axons are more energy efficient than unmyelinated axons.

Explanation:

Neurons are cells that specialize in transmitting messages to each other using a type of electrical signal. These signals carry information from outside your body to the brain, while others are the instructions for the various organs, glands and muscles to carry out functions.

Neurons receive these signals from other neighboring neurons through their dendrites. The signal then travels to the soma of the neuron, which is the main body of the cell, and finally travels down the axon to the synapse (space between the end of a neuron and another cell). The axon is a neuronal extension through which the electrical signal travels, extending from the soma to other neurons.

There may be layers of myelin, which consist of a layer of fat, covering the axons and where they have the function of acting as insulators to help keep the electrical signal inside the cell, which makes it move faster increasing the speed of transmission of the nerve impulse.

1) Myelinated axons transmit nerve impulses via continuous conduction. FALSE. In the axon, nodes of Ranvier are found at regular intervals along the length of the axon in the myelin sheath that surrounds it. These are small spaces that expose the axon membrane to the extracellular fluid and serve to allow the nerve impulse to travel faster, in a jumping manner and with less chance of error.

2) Myelinated axons transmit nerve impulses in the same manner as unmyelinated axons. FALSE. In an unmyelinated axon, the movement of voltage across the membrane is due to ion flux that is limited by the time it takes for sodium ions to diffuse into the axon. Myelinated axons conduct faster because they are shorter than unmyelinated axons. In the latter, transmission is continuous but slower.

3) Myelinated axons utilize fewer voltage-gated channels than unmyelinated axons of the same length and diameter. TRUE. The action potential conduction jumps from node to node, thereby they need fewer voltage-gated channels. Unmyelinated axons need voltage-gated channels in along the entire axon.

4) Myelinated axons are more energy efficient than unmyelinated axons. TRUE. The rate at which sodium input through one node can depolarize the axon at the next node is related to the current and capacitance across the membrane. Myelinated axons have faster action potential conduction because it jumps from node to node, thereby they use less energy because they don't have to travel the entire length.

5) Myelinated axons would be unaffected by diseases that attack the CNS. FALSE. For example, Multiple sclerosis (MS) is a demyelinating disease of the CNS in which the immune system attacks the myelin sheath or the cells.