Lias conducted an experiment about the effects of exercise on the heart rate of teenagers. before morning basketball practice, he asked the members of his high school team to be his subjects. he measured each of their heart rates before and after a set of exercises. which change would most reduce the bias of his experimental design? test the team members on the same exercises after practice too. test additional boys as well as several girls from different classes. test girls from his school, as well as teachers, siblings, and family friends. test the team members every day for a week to increase data.

Read this summary of a scientific theory: "cells are the most basic structural and functional units of life. all living organisms are made up of one or more cells. all cells that are alive in the world today came from pre-existing cells." which of the following would require this theory to be modified? -a.) a survey finds that a majority of people believe viruses carry out the basic processes of life. -b.) a prominent scientist says she feels strongly that one day the theory will be challenged by life on other planets. -c.) the dna of unicellular and multi-cellular organisms is shown to have many fundamental similarities. -d.) scientific observations show that microscopic organisms living in the deep ocean are not made up of cells.