Answer:
It helps prevent invasive species from coming in.
Explanation:
Invasive species ruin habitats because they have no natural predators, so they grow and mooch off of native species which kills them off.
The transmission of an impulse is made possible first by electric signals propagating within a neuron. Then, at the end of the axon called a synapse, chemical substances called neurotransmitters get released to transmit the message. These neurotransmitters then attach to chemical receptors in the following neuron.
Answer: Atmosphere
Explanation:
Atmosphere is the part of the earth, known as the gaseous part, since it contains gases such as nitrogen (about 78%), oxygen (about 21%), Carbondioxide (about 0.03%), and rare gases to make the rest.
Thus, atmosphere contains the most whole of oxygen and carbon dioxide
Pi and sigma bonds
Pi is double bonds and sigma is single bonds