Answer: C) As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth.
Explanation:
Growth factors are proteins that stimulate cell division.Two of the most important internal factors are kinases and cyclins. In most mammal cells stop dividing once they touch other cells this means that when a cell population reaches a certain density, the amount of required growth factors and nutrients available to each cell becomes insufficient to allow continued cell growth.
Answer:
The scar on its ear
Explanation:
The scar is not an action/trait of the AE. It is something that is lleft behind from an event. Not all AE have them.
I wish you luck! :)
<h3><u>Answer;</u></h3>
d. a neuron recharges before it can fire again.
<h3><u>Explanation;</u></h3>
- <em><u>Refractory periods are a short phase in time following an action potential where another action potential cannot be generated. </u></em>
- <em><u>It is the period immediately following the transmission of an impulse in nerve or muscle, in which a neuron or muscle cell regains its ability to transmit another impulse. </u></em>
- There are two types of refractory period, that is the absolute refractory period and the relative refractory period. Absolute refractory period is the first part of a refractory period during which, the neuron will not fire again no matter how great the stimulation and this only lasts for a short time.
- Relative refractory period occurs when a stronger than usual stimulus is required to trigger the action potential before the neuron returns to resting state.
Answer:
Melanin is responsible for black colour of hair.
Explanation:
Hair is black in colour because it is determined by the amount of a pigment present in hair is called melanin. If eumelanin which is a type of melanin, present in hair, it gives people black or brown hair. If the receptor is not activated or is blocked in the hair, then melanocytes make pheomelanin instead of eumelanin and then the black or brown hair colour did not occurs so we can conclude that melanin is responsible for black colour of hair.
