Vitamin d-3 is synthesized in the skin in response to sun exposure. question 5 options: a. true b. false

Which of the following is true of microbes? a. ninety-nine percent of all microbes are pathogenic. b. gene expression in bacteria is very similar to gene expression in humans, which facilitates the use of bacteria in recombinant biotechnology and gene therapy. c. all bacterial enzymes are harmful to humans and the environment. d. microbes create pollutants and toxins that harm the environment.

Some mining processes involve removal of large areas of earths surface in the mined region this practice causes severe environmental damage by allowing which natural process to accelerate in the affected areas? a. precipitation b. erosion c. migration d. condensation

Which of these is most likely to happen if parallax measurements of star distances are taken after a gap of six months? the results would be accurate the results would be inconsistent the results would not be valid the results would not be repeated