Answer:
Neurons, as with other excitable cells in the body, have two major physiological properties: irritability and conductivity. A neuron has a positive charge on the outer surface of the cell membrane due in part to the action of an active transport system called the sodium potassium pump. This system moves sodium (Na+) out of the cell and potassium (K+) into the cell. The inside of the cell membrane is negative, not only due to the active transport system but also because of intracellular proteins, which remain negative due to the intracellular pH and keep the inside of the cell membrane negative.
Explanation:
Neurons are cells with the capacity to transmit information between one another and also with other tissues in the body. This information is transmitted thanks to the release of substances called <em>neurotransmitters</em>, and this transmission is possible due to the <em>electrical properties </em>of the neurons.
For the neurons (and other excitable cells, such as cardiac muscle cells) to be capable of conducting the changes in their membranes' voltages, they need to have a<em> resting membrane potential</em>, which consists of a specific voltage that is given because of the electrical nature of both the inside and the outside of the cell. <u>The inside of the cell is negatively charged, while the outside is positively charged</u> - this is what generates the resting membrane potential. When the membrane voltage changes because the inside of the cell is becoming less negative, the neuron is being excited and - if this excitation reaches a threshold - an action potential will be fired. But how does the voltage changes? This happens because the distribution of ions in the intracellular and extracellular fluids is very dissimilar and when the sodium channels in the cell membrane are opened (because of an external stimulus), sodium enters the cell rapidly to balance out the difference in this ion concentration. The sudden influx of this positively-charged ion is what makes the inside of the neuron become less negative. This event is called <em>depolarization of the membrane</em>.
Lthough much of the explanation for why certain substances mix and form
solutions and why others do not is beyond the scope of this class, we
can get a glimpse at why solutions form by taking a look at the
process by which ethanol, C2H5OH, dissolves in
water. Ethanol is actually miscible in water, which means that the two
liquids can be mixed in any proportion without any limit to their
solubility. Much of what we now know about the tendency of particles
to become more dispersed can be used to understand this kind of change
as well.
Picture a layer of ethanol being carefully added to the top of some water (Figure below).
Because the particles of a liquid are moving constantly, some of the
ethanol particles at the boundary between the two liquids will
immediately move into the water, and some of the water molecules will
move into the ethanol. In this process, water-water and
ethanol-ethanol attractions are broken and ethanol-water attractions
are formed. Because both the ethanol and the water are molecular
substances with O−H bonds, the attractions broken between water
molecules and the attractions broken between ethanol molecules are
hydrogen bonds. The attractions that form between the ethanol and
water molecules are also hydrogen bonds (Figure below). There you go
Answer:
they both have nucleus, cytoplasm, cell membrane and mitochondria
Explanation:
Answer:
Gravity
Explanation:
Percolation is the process of a liquid slowly passing through a filter. It's how coffee is usually made. Percolation comes from the Latin word percolare, which means "to strain through." Percolation happens when liquid is strained through a filter, like when someone makes coffee.
Evaporation-the process of turning from liquid into vapor.
Condensation-water which collects as droplets on a cold surface when humid air is in contact with it.
and gravity- Gravity is the force of attraction between two objects, and Earth's gravity pulls matter downward, toward its center. It pulls precipitation down from clouds and pulls water downhill. The warm water near the surface of the ocean heats up with sunlight and evaporates, keeping the water cycle in motion.
I believe the correct answer among the choices presented above is the last option. It is in the Sahara desert that most-likely there is physical water scarcity. This is because it is a desert and it is a characteristic of a desert to have very small or no amount of water. Also, the climate their is very hot.
