Answer:
Small cells have a smaller surface-to-volume ratio than
larger cells.
Cell membrane allows some material to pass through it while on the same time it blocks other material from entering through it
Answer:
The correct answer is c) action potential
Explanation:
Action potential starts with the opening of the sodium channel in response to the stimulus given to the neuron by neurotransmitter. This opening of sodium ion channel results in the influx of sodium ions in the receptive region of neurons from outside. This is the depolarization step of action potential.
Before this step, the neurons are negatively charged from inside and positively charge outside and this stage it is considered to be resting stage.
As the amount of Na⁺ reaches the threshold value the action potential fires and send the electric signals down to axons.
Therefore action potential occurs because of the influx of Na⁺ ions through chemically gated channels in the receptive region of a neuron.
The central nervous system includes the brain and spinal cord.
When a cell divides by way of mitosis, it produces two clones of itself, each with the same number of chromosomes. When a cell divides by way of meiosis, it produces four cells, called gametes. Gametes are more commonly called sperm in males and eggs in females.