Final answer:
A drop of blood contains a multitude of red and white blood cells vital for oxygen transport and immune defense, respectively. Erythrocytes carry oxygen with hemoglobin, while leukocytes protect the body against infection.
Step-by-step explanation:
A single drop of blood contains 225 red blood cells and 223 white blood cells. The content loaded within a drop is significant as it comprises millions of cells that are essential for carrying oxygen and defending the body against infections. Red blood cells, or erythrocytes, are numerous and primarily function to transport oxygen due to the presence of hemoglobin, the iron-containing protein. These cells are produced in the bone marrow and have a lifespan of approximately 120 days. Unlike red blood cells, white blood cells, or leukocytes, are larger in size but fewer in number.
Leukocytes play a crucial role in the immune response; they include different types such as neutrophils, monocytes, lymphocytes, eosinophils, and basophils. Each of these cells works strategically to identify and eliminate pathogens. Platelets, another significant component, are not mentioned in the quantity in the question but are vital for blood clotting and to prevent blood loss after injury.