Jaoquin buys 3 dozen lightbulbs. after changing the lightbulbs in his house, he has 15 lightbulbs left. how many lightbulbs did he use? explain your work. i need the like right

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these

The hershey and chase experiments involved the preparation of two different types of radioactively labeled phage. which of the following best explains why two preparations were required? a. the bacteriophage used in the experiments was a t2 phage. b. it was necessary that each of the two phage components, dna and protein, be identifiable upon recovery at the end of the experiment. c. each scientist had his own method for labeling phage, so each conducted the same experiment using a different isotope. d. establishing the identity of the genetic material required observation of two phage generations.

Approximately how many times does an average human heart beat in a lifetime?