The right answer is D (less responsive to antigens)
It is proven that, after puberty, thymus activity (an organ that is included in the lymphatic system, producing T cells that pick up antigens) decreases and that in adult and aged people the thymus has no role. Work done in humans indicate that in fact the cellularity begins to decline from birth in favor of lymphocyte perivascular spaces and connective and adipose tissue, which leads to a decrease in the capture of antigens.
Answer:
When diverse molecules and objects are brought together, they generate a chemical, which causes sickness. Forest fires can occur spontaneously or as a result of human activity. Natural factors include severe droughts and a lack of precipitation. Campfires or the usage of a flare gun can be used to create man-made causes.
Water molecules consist of 2 Hydrogen and 1 Oxygen atom. They are bonded by a polar covalent bond, meaning the electrons shared by the covalanet bonds are not evenly distributed. Oxygen is more electronegative than Hydrogen and will pull the electrons from its bonds with Hydrogen closer to itself. Thus results in a partial positive dipole on the Hydrogen of the water molecule and a partial negative dipole on the Oxygen of the water molecule. These partial charges allow water to hydrogen bond with one another through a process called cohesion.
