What is the time that it takes for half of the chemical or toxin to be expelled from the body?

How can lung cancer best be prevented? a. by getting regular screeningsc) b. by avoiding cigarette smokec. by monitoring cholesterol levelsd. by avoiding nown allergensherrwww

Aresearcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (tmv). the cell contents are left in a covered test tube overnight. the next day this mixture is sprayed on tobacco plants. we expect that the plants would ) develop some but not all of the symptoms of the tmv infectionb) develop the typical symptoms of tmv infectionc) not show any disease symptomsd) become infected, but the sap from these plants would be unable to infect other plants

Effective antiviral drugs are usually associated with which of the following properties? a) interference with viral replicationb) prevention of the host from becoming infectedc) removal of viral proteinsd) removal of viral mrnas