tricuspid valve is located between the right atrium and ventricle
Answer:
Explanation:
The cell membrane separates the cell from the outer environment. The extracellular fluid contains the sodium ions (Na+), chloride ions (Cl-), while intracellular fluid contains potassium (K +) and negative anions.
The potential difference arises when the membrane is selectively permeable to some ions. The resting potential is -70mV.
When the neurons get excited, the sodium ions start to enter by sodium channels.
Now there are more positive ions inside the cell membrane. It disturbs the resting potential i.e. -70mV. This stage is known as depolarization.
When the inside environment of the cell is more positively charged, the potassium ions start to move out of the cell. It goes out by the voltage-gated channels. Thus resting stage is maintained and it is known as repolarization.
But the initial stability of the cell membrane has to be maintained. To restore the resting stage, the sodium ions start to move out of the membrane and potassium ions enter into the cells again. This is an active transport and has done by the Na+ - K+ pump. Here 3 sodium ions move out and 2 potassium ions pumped into the cell through the plasma membrane.
Thus the resting potential regains. The potassium ions come back into the cells against the concentration gradient and ATP provides the energy for this phenomena.
So understanding<span> how the </span><span>DNA </span>molecule behaves inside cells<span> helps explain how genetics works</span><span> at the simplest level. </span>
"Marsh" ecosystem has the "greatest biodiversity".
Option: C
<u>Explanation</u>:
Marsh or Wetland ecosystem is highlighted as “biological super systems” as it is responsible to manufacture giant volume of meal that favors large amount of biodiversity, which is rich as rain forests and local reefs. The combination of important nutrients, shallow water and large primary productivity is basic source for Earth's food web. For example such food web is supported by birds, shellfish, fish, amphibians and insects. This ecosystem helps filtration of pollutants and soil runoff from the upstream sources which in return support river, ocean and bays in cleaning downstream.
Answer:
vestigial structures are considered evidence because scientists believe they are structures that were once used by a species ancestors but are not longer needed. these structures do not impair the organism in any way, so there is no need for evolution to get rid of them. for example, the human appendix is considered a vestigial structure.
Explanation:
:D
