Ameteorite is determined to be 4.5 billion years old. it now has 78 atoms of lead-206. assuming no loss of daughter isotopes, how many atoms of uranium-238 did the meteorite have to begin with? the half-life of uranium-238 is 4.5 billion years. a) 156 b) 312 c) 78 d) 238

When should a bar graph be used? a. when there is no independent variable. b. when the independent variable is continuous and does not show a relationship to the dependent variable. c. when the independent variable is continuous and shows a causal link to the dependent variable. d. when the independent variable is composed of categories and does not show a relationship.

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.

Arepair man charged $93.06 the price included 2 hours of labor and 40 service charge how much does the repairmen charge per hour for labor?