A(n) refers to a substance or treatment that is often used in an experiment but does not have an actual medicinal or experimental benefit. a. extraneous variable b. placebo c. confounding variable d. independent control  

Your town is considering building a biodiesel power plant describe at least two advantages and two disadvantages

An astronaut on the moon throws a baseball upward. the astronaut is 6 ft, 6 in. tall, and the initial velocity of the ball is 3030 ft per sec. the height s of the ball in feet is given by the equation s equals negative 2.7 t squared plus 30 t plus 6.5s=−2.7t2+30t+6.5, where t is the number of seconds after the ball was thrown. complete parts a and b.

The diagram shows a wave. the quantity shown is the amplitude. this quantity is directly proportional to which of these other quantities? a) energy b) frequency c) period d) wavelength