Which factor is difficult to assess in a cost–benefit analysis? a. product being used by everyone b. the aesthetic value of nature c. identifying internal costs d. categorizing internal and external costs

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

Which of the following does not make up ground substance of connective tissue? hyaluronic acid elastic fibers glycosaminoglycan proteoglycan

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?