Which of the following is smallest?
Eukaryote cell
Bacteria
Bacteriophage
Cell membrane protein

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate