The walls of the cell membrane is what strengthens it
Fires disrupt the equilibrium of an ecosystem. The results of a fire include a resetting of plant succession. Many ecosystems have adapted to a certain frequency and intensity of wildfires, and many plant species actually require fires as part of their life cycles. Fires can open up forests and grasslands that would be too congested and shaded to allow young grasses or trees to take root. Fires in fact act as a stimulus for some seeds to germinate. These would typically be pioneer plants that are able to grow in fairly harsh and varied conditions. Fires also remove accumulated dead tree matter that can accumulate in a forest, and if wildfires are too infrequent, fires and be very intense when they do happen as they are fed by the accumulated material.
Bees impact the environment because they support the growth of flowers and plants and the produce honey.
Fossils prove that other organsism lived before us and show organisms simmalar to us
Answer:
The sodium channel have refractory period.
Explanation:
Action potential are generated at axon hillock of neuron and travel across the neuron in response to stimuli. For the the generation of action potential the steps are stimulus, depolarization, repolarization, hyperpolarization and resting state.
So the first step for action potential after stimulus is depolarization. Depolarization requires the opening of sodium channels to make the inside of neuronal membrane positive. These sodium channels have refractory period. They cannot open immediately after activation. So the sodium channels of one direction in neuron (upstream) become refractory and it is convenent to open the sodium channels of other direction (downstream) of neuron. That why action potential is transmitted in one direction.
It is like the gunpowder placed at a line the fire cannot go back in burnt gun powder direction.
