In addition to the six elements most prevalent in living things there are other elements that are required for human life. which element is necessary for humans to maintain a strong skeletal system?
a. xenon
b. calcium
c. rhodium
d. chlorine

It is important to wear proper protective equipment in lab even when not actively performing experiments because accidents can affect any researcher, even one not working on an experiment. select the best answer from the choices provided

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Why did southern business leaders want to increase the number of slaves