Most irregular galaxies are thought to have formed from <span>collisions between other galaxies.
This is just one wat that irregular galaxies are formed; the collision is due to the interaction of their gravitational forces. These galaxies might have been regular before the collision, but are not deformed.
Another form of irregular galaxies are the ones that are still very young and therefore have not yet reached their symmetrical state.</span>
A Nerve electrical impulse only travels in one direction. There are several reasons nerve impulses only travel in one direction. The most important is synaptic transport.
In order for a "nerve impulse" to pass from cell to cell, it must cross synaptic junctions. The nerve cells are lined up head to tail all the way down a nerve track, and are not connected, but have tiny gaps between them and the next cell. These tiny gaps are called synapses.
When you get a nerve firing, you have probably heard that it is an electrical impulse that carries the signal. This is true, but it is not electrical in the same way your wall outlet works. This is electrochemical energy. Neurotransmitters are molecules that fit like a lock and key into a specific receptor. The receptor is located on the next cell in the line. When the neurotransmitter hits the receptor on the next cell in line, it signals that cell to begin a firing as well.
This will continue all the way down the length of the nerve track. In a nutshell, a nerve firing results in a chain reaction down the nerve cell's axon, or stemlike section. Sodium (Na+) ions flow in, potassium (K+) ions flow out, and we get an electrochemical gradient flowing down the length of the cell. You can think of it as a line of gunpowder that someone lit, with the flame traveling down the length of it. Common electrical power is more like a hose full of water, and when you put pressure on one end, the water shoots out the other.
Therefore, nerve impulses cannot travel in the opposite direction, because nerve cells only have neurotransmitter storage vesicles going one way, and receptors in one place.
Answer:
D. Fossil record.
Explanation:
The fossil record evidences the evolutionary history of life on Earth by tracing the life forms that existed from earlier geological times and remained in the sedimentary rock. Different fossils were dated in the sedimentary rocks of all geological periods. The simplest forms of life were discovered in the oldest rocks, while more complex fossil organisms were found in the newest rocks. In consequence, the fossil record can support the evolutionary process as proposed by Charles Darwin, who indicated that the simplest forms of life evolved in more complex organisms.
It's a decomposition reaction. It's a chemical reaction because one substance (H2O2) is breaking down and becoming 2 completely new substances (H2O and O2)
Answer:
70 million people are added
Explanation:
