Answer:
the answer for your question is 3 and 4
Sorry there are no answer choices
The right answer is B.
*Hydrogen is the most abundant element representing nearly three quarters of the mass of the universe.
*Hydrogen is found in the water that covers 70% of the surface of our planet as well as in all organic matter.
*Hydrogen is the simplest element in the universe. It is composed only of one proton (p) and only one electron (e-).
*Hydrogen is the lightest element of all elements and gases; it is 14 times lighter than air. A "spill" of hydrogen gas immediately diffuses into the air and pollutes neither the ground nor the water table.
*Hydrogen is invisible, odorless and nontoxic. It does not cause acid rain, does not deplete the ozone layer and does not generate dangerous emissions.
Action potentials travel swiftly down: axons with myelin and more slowly in axons without myelin.
The conduction velocity of the action potential is faster in myelinated axons, the nerve impulse generated by an action potential can propagate faster than it loses its strength due to the insulation that protects against signal loss. Similar to the insulation around wires in electrical systems, glial cells form a membrane sheath surrounding axons called myelin, insulating the axon. This myelination, as it is called, can greatly increase the speed of signals transmitted between neurons. The action potential travels down the axon as a result of sodium influx depolarizing near-threshold segments of the axon. A voltage change that reaches a threshold value causes voltage-gated sodium channels in the axonal membrane to open.
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Answer:
C
Explanation:
deer are alive and therefor biotic. As they graze they eat grass, walk on land and use oxygen, - all parts of the environment