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.
Answer:
B. runoff of nitrates from fertilizers applied to the golf course
Explanation:
Algal bloom is defined as the rapid growth of algae in freshwater or marine water. Algal bloom is green or yellowish in color that cover the top layer of water systems.
Algal bloom in the given case is caused by the excess of nutrients that is nitrates from fertilizers into waters and higher concentrations of nitrates causes uncontrollable growth of algae.
Algal blooms are harmful for environment as they may produce toxins and can block the sunlight from reaching the plants and animals in the water systems.
Hence, the correct answer is "B. runoff of nitrates from fertilizers applied to the golf course".
The following choices are provided;
- Earthquakes release phosphorus.
- Phosphorus is carried in the rain that was evaporated from lakes.
- Human use of fertilizers releases phosphorus into the groundwater.
- Phosphorus is transpired.
The answer is; Earthquakes release phosphorus
Phosphorus is usually made less available to plants and to the rest of the ecosystem through runoffs. The washed-off phosphorus is deposited at the oceans- and seabeds with sediments. This phosphorus is made available again due to tectonic plate movements. Tectonic movements may cause earthquakes that expose these sediments to the earth’s surface.This uncovers the sedimentary rocks to agents of weathering and hence the elements are more available to living organisms on the surface.
A dominant allele can produce a dominant phenotype in individuals with one copy of the allele from one or both parents, but a for recessive allele to produce a recessive phenotype, the individual needs to have two copies, one from each parent.
