Which 2 organ systems work together to break down and deliver food molecules to cells A. Cardiovascular and immune
B. Nervous and muscular
C. Digestive and cardiovascular
D. Respiratory and cardiovascular

PLEASE HURRY I NEED THIS ANSWER

In a sample of oxygen gas at room temperature, the average kinetic energy of all the balls stays constant. which postulate of kinetic molecular theory best explains how this is possible? a. attractive forces between gas particles are negligible because the particles of an ideal gas are moving so quickly. b. collisions between gas particles are elastic; there is no net gain or loss of kinetic energy. c. gases consist of a large number of small particles, with a lot of space between the particles. d. gas particles are in constant, random motion, and higher kinetic energy means faster movement.

Which sentence best describes the formation of igneous rock? a- lava on the surface dries up and makes arock b_melted rocks cools and forms crystals c_rocks under tremendous heat and pressure d_magma is melted rock underground

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit