Why am i breathing through one nostril? it's making it hard for me to sleep, and depending on which side i lay one it will go to that side of the nostril.

Which of these is most likely to prevent pregnancy? a. tracking of female body temperature to identify ovulation times b. proper condom use c. male withdrawal before ejaculation d. proper spermicide use

What are your thoughts on nonhuman trials? do you feel that testing should be done on animals? what are the advantages and disadvantages with nonhuman trails?

Wjat are substances intentionally added to food to produce a desired effect?