Duchenne muyscular dystrophy is caused by a mutation on the X chromosome, so a male gets it from his mother's X, if she is a carrier. The male child gets a Y and no X from his father, so the disease is always transmitted through the X from the mother. If a female gets Duchenne muscular dystrophy she has to have two X chromosomes, one from a carrier mother and another from from an affected father. This is virtually impossible because most males die before childbearing age and there is no way a female child can get an X from a man who does not live long enough to procreate. About eight percent of carrier women do show some muscle weakness, but they do not have the disease.
Answer:Mechanical digestion physically breaks down food, like when teeth macerate food into a bolus. The stomach contracts and relaxes in a churning motion. ... Chemical digestion occurs when the bonds within larger food molecules are broken, creating smaller molecules that the body can use.May 30, 2017
Explanation:
True, there are many vessels serving as a conduit<span> between the lungs and the heart.
The number of the vessel is many because all the carbon dioxide from body need to be released at the lungs. More vessel means more surface area and blood flow rate to do the diffusion of the gas which means increased diffusion rate. This will allow the lung to transfer oxygen and dump carbon dioxide faster.</span>
<span>Unicellular organisms would most likely have isogametes.
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