When the stimulus voltage is increased, . When the stimulus voltage is increased, . sodium permeability into the cell decreases sodium permeability into the cell increases to overcome the potassium exiting a greater-than-threshold depolarization results a greater-than-threshold depolarization results and sodium permeability into the cell increases to overcome the potassium exiting.

a greater-than-threshold depolarization results and sodium permeability into the cell increases to overcome the potassium exiting.

Explanation:

The occurrence of action potential requires the existence of active voltage-dependent channels to open and close in response to the membrane depolarization.  

When depolarization reaches and supers the threshold point, voltage-dependent Na+ channels open and the ion gets into the cell. The entrance of Na+ decreases the electric charge difference between the cellular interior and exterior. Membrane depolarizes and produces the action potential that tends to reach a potential equilibrium for Na+ = +60mV. The higher the Na+ input is, the greater is the depolarization and the greater is the Na+ permeability.

Once Na+ channels are closed, voltage-dependent K+ channels open, increasing the membrane permeability to the ion, letting K+ get out of the cell, following the electrochemical gradient.  

The closure of Na+ channels and opening of K+ channels are responsible for membrane repolarization.

answer: after carbon dioxide enters the leaf through stomata it moves into the mesophyll cells where photosynthesis occurs and glucose is constructed. respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce useable cellular energy.

explanation:

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle