What does this symbol ∞ means in mathematics?

Which statement is true about common childhood infectious disease? a. children should always be given antibiotics to treat an infectious illness. b. frequency of infectious illnesses usually increases as children grow older. c. having a minor infectious illness weakens a child's immune system. d. infectious illnesses are usually mild and require no medication.

Alcohol is a dangerous drug because it a can change the way the mind and body function. b changes the way you look to other people. c makes you believe you are invincible. d cannot absorb into the bloodstream.

Which term matches this definition? treating all human blood and other potentially infectious material, as if known to be infectious, for bloodborne pathogens. a. exposure control plan b. engineering controls c. universal precautions d. personal protective equipment