The fatty substance that insulates and protects the axon is myelin sheath. That is option D.
<h3>The nerve cells (neuron)</h3>
The nervous system is made up of nerve cells that helps to send and receive signals that are interpreted by the brain.
The parts of the nerve cell include the following:
The axon is part of the nerve cell that transmits electrical signals. it is surrounded by myelin sheath.
The myelin sheath is a fatty layer that insulates the axon and helps it transmit signals over long distances.
Therefore, the fatty substance that insulates and protects the axon is myelin sheath.
Learn more about neurons here:
brainly.com/question/13061744
The driving force for the movement of lithosphere plates is convection currents. These currents are found in the inner core of the earth and take the heat from the core to the lithosphere. Tectonic plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere. Dissipation of heat from the mantle is acknowledged to be the original source of energy driving plate tectonics. The current view, although it is still a matter of some debate, is that excess density of the oceanic lithosphere sinking in subduction zones is the most powerful source of plate motion.
Answer:
Proteins and lipids exist as separate but loosely attached molecules that can move around
Explanation:
Cell membranes are mainly composed of lipids, proteins, and also carbohydrates. Phospholipids are the most abundant type of lipid and the main constituent of the cell membranes. Membrane proteins are divided into two types according to their interactions with the cell membrane: 1-integral (intrinsic) and peripheral (extrinsic) proteins. These peripheral proteins are loosely attached by ionic bonds or calcium bridges with the phosphate heads of the phospholipids; whereas integral membrane proteins contain side chains that interact with fatty acyl groups of the phospholipids. Cell membrane fluidity indicates how easily lipids (e.g., phospholipids and cholesterol) and proteins (e.g., intrinsic proteins) diffuse laterally in the cell membrane. This fluidity is affected by the amount of cholesterol, temperature, and the ratio of unsaturated to saturated fatty acids. Saturated fatty acids have no double bonds in the hydrocarbon chain, whereas unsaturated fatty acids have at least one double bond (these double bonds increase fluidity). Moreover, higher temperatures increase membrane fluidity, whereas cholesterol molecules function to regulate membrane fluidity: at high temperatures cholesterol molecules stabilize the membrane, whereas at low temperatures intercalate between phospholipids, thereby preventing them from clustering together.
