Why are dead or weakened viruses used instead of normal viruses to create a vaccine?

Which best example best demonstrates the importance of having knowledge of evolutionary relationships? a. illustration of a plant b.organ transplantation between species c. blood donation from a human d. do you need sequence of an insect.

Graded assignment lab report answer the questions below. which combinations of substances resulted in a chemical change? for each metal that participated in a chemical change, write the type of metal it is, based on your examination of the periodic table. were there any metallic compounds that did not react with either the acid or the base? write the type of metal, based on your examination of the periodic table. make a general statement about the reactivity of the metals in this experiment.

Some substances but not other can cross the (blank) membrane of a cell