True or false? factors such as the hormonal varations caused by the menstrual cycle and the possible effecdts of a trial on a developing fetus can pose statistical and ethical challenges.

Which of these is not a function of some membrane proteins ? a. allowing polar molecules to enter the cell b. recognizing other types of cells c. receiving messeges from other cells b. carrying messages to oher cells

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

What happens whenever a net force acts on an object