Why do vaccines work for some diseases but not others?

Growth of chest hair, deepening of the voice, and muscle growth are secondary sex characteristics. which most likely affects the development of these traits? testes ovaries prostate gland vulva

20 points and brainlist 1. london has suffered from terrible air pollution for at least seven centuries. why is the city so prone to its famous “london fog? ” what did london do to get rid of its air pollution? 2. why does air pollution cause problems in developing nations more than in developed ones?

What are two examples of conduction that we use everyday