the isotope radium-226 decays into radon-222, with a half-life of around 1,600 years. if a rock contained 6 grams of radium-226 when it reached its closure temperature but only 0.375 grams when it was discovered , which two statements about the rock are true.

Ohm's law tells you that i = v/r where v is equivalent voltage and r is equivalent resistance of the circuit
since all circuits have the same voltage, your question is really asking which circuit has the lowest total resistance, since the lower the resistance, the higher the current
circuit a has a resistance of 5 ohms; circuit c is in series so has a resistance of 10 ohms; circuit b is in parallel and therefore has a resistance of 2.5 ohms (review your notes on adding resistances in parallel and series); therefore b has the highest current

Well i am not very good at this but  i would be guessing 1hope i  

Gravity, from the center of mass of the box, extending downward normal force, from the floor under the box, extending upward, equal to gravity push force, acting at a point on the box, extending in the direction of motion friction, acting at any point on the box directly opposite the push, extending directly opposite to the motion

Fb is the magnetic force  q is the chargev is the velocity of the charge  b is the magnetic field  the equation is: f=|q|vbsin0