A genetic mutation causes a disease when the the DNA encodes is altered such that it no longer functions properly. Errors during can cause genetic problems with the resulting germ cells. Down syndrome is caused by three copies of chromosome 21, also known as 21. A silent mutation is a change in the DNA that does not change the encoded , and has no phenotypic effect.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

carbon traps heat so more of it makes it hotter causing global warming. during the ice age carbon levels in the atmosphere were low so it got very cold. so the common things between them is carbon levels in the atmosphere.

answer///island,peninsula;