Answer:Carbon has four valence electrons, so it can achieve a full outer energy level by forming four covalent bonds. When it bonds only with hydrogen, it forms compounds called hydrocarbons. Carbon can form single, double, or triple covalent bonds with other carbon atoms.
Explanation:
 
        
             
        
        
        
Answer:
3.5 percent (3.5%)
Explanation:
In genetics, <em>crossing over</em> or 'recombination' refers to the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis I. The map units (m.u.), also known as centimorgans, represent a measure of genetic linkage between genes/<em>loci</em> located on the same chromosome. One map unit (1 m.u.) is equal to a 1 percent chance that two gene/<em>loci</em> (in this case, genes H and K) will be separated during meiosis by recombination. In the example above, it means that among their progeny, 3.5 percent (3.5%) will be recombinant for the two genes (H and K), and 96.5 percent (96.5%) will have the parental combination of these genes.
 
        
             
        
        
        
When researchers examine these damaged nerves, they find that the myelin insulation is often gone and the axons are destroyed. These changes prevent nerves from transmitting messages properly.
A
        
             
        
        
        
The nervous and the endocrine system are tightly linked together.
The main reason for this linkage is due to the connection of the hypothalamus (nervous system) and the hypophysis (a gland in the endocrine system)
The hypophysis is the ''controller'' of all of the other endocrine glands.
The connection between the hypothalamus and the hypophysis enables the nervous system to control the hormone levels of all of the major endocrine glands in the body.
The hypothalamus releases hormones into the bloodstream that leads to the hypophysis. These hormones induce a release of hypophysis hormones that enter the bloodstream and when they reach the target gland (for example pancreas) these hormones induce the release of the hormones of that gland (in the case of the pancreas, insulin).
The hypothalamus monitors the concentration of hormones in the blood, and a high level of a certain hormone blocks the release of the hypothalamus' hormones. Therefore, a high level of insulin blocks a cascade of hormone release that starts in the hypothalamus that leads to its release in the pancreas.