Which structure of the male reproductive system from the following image stores the mature sperm before ejaculation?

A. Lysozyme within tears destroy bacteria.: Lysozyme is an enzyme found in tears that helps to break down the cell walls of bacteria, acting as a chemical barrier and part of the innate immune system's first line of defense.

B. Chemotaxis attracts phagocytes to the site where the pathogen invaded.: This is part of the inflammatory response, which occurs after the first line of defense has been breached; therefore, it is not considered a first line of defense action.

C. Natural killer cells are the first lymphocytes to react to infection.: While natural killer cells play an essential role in the immune response, they are part of the second line of defense and respond after pathogens have entered the body.

D. Phagocytes ingest microbes when they enter the body.: This is part of the second line of defense, as phagocytes respond to pathogens that have breached the first line of defense, which includes physical and chemical barriers.

A. Increased afterload: Increased afterload, the resistance the heart must overcome to eject blood, typically reduces stroke volume because the heart has to work harder to push blood against higher pressure.

B. Decreased heart contractility: This would reduce stroke volume, as the heart would be less effective at pumping blood.

C. Increased preload: Preload refers to the volume of blood in the ventricles at the end of diastole. An increased preload stretches the heart muscle, which typically leads to a stronger contraction and higher stroke volume.

D. Decreased blood pressure: While low blood pressure may reduce afterload, it doesn't directly increase stroke volume unless other factors are at play.