Answer:
the degree to which they decrease CNS activity
Explanation:
Drugs can be classified as;
✓hallucinogens, example is (LSD)
✓ stimulants, example is (cocaine)
✓opium-related painkillers example is (heroin)
✓depressants
Depressants can be regarded as medicines, that lowers neurotransmission levels, that is depressing or reducing arousal or stimulation as regards to various areas of the brain. these could be tranquilizers, as well as hypnotics and
sedatives. They are drugs used in slowing brain activity, therefore, making them useful when treating anxiety, sleep disorders, panic and acute stress reactions.
Example of Depressants are;
✓Xanax
✓Halcion
✓Klonopin
✓Librium
It should be noted that Depressants are often classified according to the degree to which they decrease central nervous system (CNS) activity.
The sideways and downward movement of the edge of a plate of the earths crust into the mantle beneath another plate
Becouse melting point and cooling point are two opposite things one is 100degrees nd other 0degrees
Explanation:
(1). It is known that in a reaction equation, reactants are placed or written on left hand side and products are written on the right hand side.
For example, 
Hence, in a reaction equation you start with the reactants and end up with the products.
(2). The number of atoms in a reaction will remain the same because according to the law of conservation of mass, mass of reactants will be equal to the mass of products.
Therefore, number of atoms on the reactant side will be equal to the number of atoms on product side.