Human physiology

Blood group O is the universal donor because its red blood cells lack A and B surface antigens, preventing an immune reaction in the recipient. Conversely, group AB is the universal recipient, not donor, because it contains both A and B antigens on its cells and lacks anti-A and anti-B antibodies.

B-lymphocytes are responsible for antibody production as part of the humoral immune response, differentiating into plasma cells that secrete highly specific antibodies. Conversely, neutrophils do not produce antibodies but instead act as phagocytic cells that engulf and destroy invading pathogens.

Fat‑soluble vitamins dissolve in lipids and are stored in the body's fatty tissues, which includes Vitamin D. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Students often assume all vitamins are water‑soluble or may mistakenly think Vitamin B12, which sounds similar, is fat‑soluble.
• !On the other hand, Vitamin C and B-complex vitamins like B12 are water-soluble and easily excreted in urine.
• !Conversely, neutrophils do not produce antibodies but instead act as phagocytic cells that engulf and destroy invading pathogens.
• !The uterus is incorrect because it is the site where the fertilized embryo implants and develops, not where fertilization itself takes place.

Answer each from memory — you'll see instantly whether you're right and why.

Run a focused 10-question mini-mock on Human physiology and see it stick.