Well, Carbon has 4 Valence Electrons. I'm sure you know this, but valance electrons allow electrons to covalently bond with one another. The elements, when sharing the electrons, want to have 8 valance electrons. So carbon has 4 valance electrons so it can bond with itself, or another say 4 hydrogen [becuase hydrogen can live with 2 valance electrons]. Hope this helps. Remember: Electrons <3 8 valance electron bonds Carbon's 4 + Carbon's 4= 8 true love at first bond! OR Carbon's 4+ Hydrogen's 1 [x4] = 8 hope this help
The answer is <span>The respiratory system supplies the oxygen that the cardiovascular system transports to the different cells for the production of energy.
When air enters the lungs (part of the respiratory system), it passes all way to the alveoli, the smallest functional units of the lung. There, oxygen from the air enters the capillaries, the smallest blood vessels, next to the alveoli. Once in the blood stream, the cardiovascular system transports oxygen to different cells where it is used for the energy production.</span>
Answer:
The mechanism that Darwin proposed for evolution is natural selection. Because resources are limited in nature, organisms with heritable traits that favor survival and reproduction will tend to leave more offspring than their peers, causing the traits to increase in frequency over generations.
The reason that natural selection is important is that it's the central idea, stemming from Charles Darwin and Alfred Russel Wallace, that explains design in nature. It is the one process that is responsible for the evolution of adaptations of organisms to their environment.
Explanation:
hope this helps
The answer is 50km your wel
Answer:
CHK2, p53, p21, cell cycle progression.
Explanation:
In a normal cell with no LFS mutation, during the G1 stage of cell cycle progression, the CHK2 activates if there is damage in the DNA. CHK2 activates p53, which is a tumor suppressor protein that will hold the cell cycle in G1/S until the DNA is repaired. The p53 protein activates p21, a protein that binds to CDK2 and stops the cell cycle. The cell cycle will continue once the damage is repaired.
