Sex<span> is determined by two chromosomes, X and Y. A female is XX, a male is XY. Since women completely lack the Y choromosome, they always contribute an X chromosome to the baby. The </span>sex<span> is determined by whether the sperm that fertilizes the egg is carrying another X or a Y.</span>
An energy resource that can be replaced by nature in a relatively short time is known as a "<span>inexhaustible energy resource" but these are very rare in nature. </span>
