Before a skeletal muscle fiber can contract

In the family tree below, people with the recessive trait of attached earlobes are shaded gray.

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Define the apical impulse and describe its normal location, size, and duration. which abnormal conditions may affect the location of the apical impulse? explain the mechanism producing normal first and second heart sounds. describe the effect of respiration on the heart sounds. describe the characteristics of the first heart sound and its intensity at the apex of the heart and at the base. describe the characteristics of the second heart sound and its intensity at the apex of the heart and at the base.