If the ratio of daughter to parent atoms in a radioactive sample is 3:1, how many half-lives have passed?

Name the organs of humanelemintary canal.

The unique structure of the neuron is dedicated to the efficient and rapid transmission of neural signals. the relationship between neurons, the spinal cord, and the brain constitutes an elaborate communication system throughout the human body. all but one of the functions listed below are a result of this interaction.

9. what area of study applies scientific findings to create ways for solving problems or improving life? a biogeology b mathematics c manufacturing d engineering