I just took a test in school today. What question was I asked?

Question I was asked: Tigers and household cats are members of the same family; however, their sizes are vastly different. What is the cause of this difference?

I just took a test in school today. What question was I asked?

Question I was asked: Why do scientists perform multiple trials of the same experiment?

I just took a test in school today. What question was I asked?

Question I was asked:
Scientists are concerned about the presence of heavy metals like lead and mercury in the environment because