Both men and women have sex chromosomes. Men usually have one X and one Y chromosome, while women have two X's.
When an egg or sperm is made, it only gets one of the sex chromosomes from the parent. This means that women can only make eggs with an X chromosome. But men can make either X or Y sperm.
During fertilization, the sperm cells race toward the mother-to-be's egg cell. If a sperm with a Y beats all others, then the fetus will be XY. The pregnancy will result in a boy.
However, if a sperm with an X wins the race to the egg, then the fetus will be XX. The parents will have a baby girl.
Nearly everyone's chances are around 50% for having a boy and 50% for having a girl. And yet, we all know families that are all boys or all girls.
<span>It
is important that antibodies have a symmetrical quaternary structure to create
two identical binding sites for antigens. An antibody is a relatively large
protein having a Y-shape. Plasma cells produce antibodies which are then used
by the immune system to fight off pathogens (e.g. bacteria and virus). The antibody
is able to recognize the antigen of the pathogen. It binds with it either to
neutralize it directly or “tag” the microbe for future attack by other parts of
the immune system. </span>
The correct option is D.
Noble gases are very stable, because they have eight electrons in their outermost shells. This is called octet form. Other elements that do not have the octet form try to achieve the form by forming bonds with other elements. Because of their stability, noble gas are chemically inert, that is, they do not undergo chemical reactions with other elements.
