Theo was doing research to support the claim that exercise increases heart and lung health. he had 50 people do a rigorous exercise program. each week, for six months, he tested their heart and respiratory rate. he determined that exercise does increase heart and lung health. which best describes his claim? a. it is valid because he used multiple trials. b. it is invalid because he did not have a control group. c. it is invalid because his sample size was small. d. it is valid because he controlled the exercise program.

The difference between two numbers is 15. when twice the smaller number is subtracted from three times the larger number, the difference is 58.what is the larger number?

Which of the following harmful chemicals are found in tobacco smoke? a. carbon monoxide b. carbon dioxide c. nicotine b. carbon dioxide d. both a and c

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?