What can cause attention deficit hyperactivity disorder (adhd)? a. low levels of gamma-amino butyric acid b. low levels of serotonin c. low levels of endorphins d. low levels of acetylcholine

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

Will give brainliest! which statement best describes the similarities between fundamental forces? electromagnetic and strong nuclear forces influence the interaction between charged particles within an atom. gravitational and magnetic forces are both types of charges that occur in nature. nuclear and magnetic forces are both related to mass and weight. strong nuclear force is most like electrical force because they are both related to distance.

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •