PLS ANSWER QUICK Index fossils help scientists estimate the age of a rock because index fossil species only existed for a relatively short time. What happened to the species that are now used as index fossils.
1. They became extinct
2.They changed diets
3.They hid in marine sediments
4.They migrated to new environments

Aperson is outside exercising. body temperature begins to rise, and the person starts to sweat. their body temperature then returns to normal, and the body stops sweating. a positive b negative c allosteric d homeopathic

Which of the following terms would bb represent in an organism? a. phenotype b. genotype c. genetics

Embryonic stem cells are cells derived from an embryo. these cells can be used to create new tissues for patients suffering from certain illnesses and disorders. which statement best summarizes why the use of embryonic stem cells could be seen as unethical? a. some people consider embryos to possess rights equal to those of fully developed human beings. b. extracting stem cells from embryos is a very energy-intensive process, which consumes resources that could be used elsewhere. c. embryos are difficult to obtain, so the monetary cost of using them for research outweighs their benefit. d. the process of extracting stem cells from embryos generates biohazardous waste that cannot be safely disposed of.