If a radioactive substance's half-life is 20 years, how much of a 40-gram sample will be left after 60 years? a. 5 grams b. 10 grams c. 20 grams d. 30 grams

(drag each tile to the correct location.) categorize each term as something that is typical of a scientific theory, a scientific hypothesis, or both. - a tentative statement used to guide scientific investigations. - makes predictions about future events. - can be tested by many independent researchers. - based on observations of natural phenomena. - a well-established, highly reliable explanation.

How are the reproductive cycles of a fungus and a pteridophyte similar? a)both organisms form fruiting bodies that produce diploid seeds. b)both organisms produce haploid spores and exhibit diploid and haploid stages. c)both organisms reproduce sexually when two haploid hyphae fuse. d)both organisms exhibit a diploid stage and are only able to reproduce asexually.

The nursing instructor has been observing nursing students initiate an iv infusion. which action(s), if made by the nursing student, indicates that further instruction is needed? (select all that apply.) the nursing student: