Dora rolled a marble down a ramp and recorded the potential energy and kinetic energy of the marble at different positions on the ramp, as shown in the table. Marble experiment
Height of
Marble from Ground (meters) Potential Energy of
Marble (Joules) Kinetic Energy of
Marble (Joules) Total Energy of
Marble (Joules)
Trial 1 1 2 4 6
Trial 2 2 4 2 6

Which is the constant variable in this experiment?
Mass of marble
Kinetic energy of marble
Potential energy of marble
Height of marble from ground

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

Cold case files recently began re-investigating an old murder case. the murder took place in the park; a young man, james, was hit over the head with a brick and killed. police suspected the jealous former boyfriend of james' wife, karen. whoever killed james may have washed their hands in a near-by bird bath as detectives found blood in the bird bath. since the murder took place before dna fingerprinting was available, the suspected killer, ronnie, went free. detectives are now reviewing the blood evidence using dna fingerprinting. based on the dna fingerprints of all possible suspects, who is james' killer?

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell