A400-gram sample of a radioactive nuclide is left to decay for 30 hours. at the end of 30 hours, only 200 grams of the sample is left. what is the half-life of the nuclide sample

a) 10 hours
b)1.5 days
c) 30 hours
d) 0.5 hours

Ascientist separates a population of mice into two groups. what would most likely increase the rate of speciation in this population. a. teach the two groups different tricks b. allow the two groups to breed with each other c. put the two groups in different environment d. have the two groups live in identical ecosystems

Nucleic acid certain protein cell membranes certain carbohydrates

In which state was more than 100 billion tons of coal mined in 2005?