Which of the following represents the four means of modifying behavior discussed in operant conditioning

24-karat gold is considered to be pure gold. 18-karat gold is considered to be about 75% gold. what is 18-karat gold considered a mixture rather than a pure substance? a) it has a variable composition of other elements and minerals. b) its color is different than pure gold. c) the gold atoms are not arranged in a repeating pattern. d) it can be melted and transformed into a different substance.

In what way was family life impacted by industrialization? a. there was a rise in the middle class. b. there was a decrease in the birth rate. c. women were not allowed to work in factories. d. families relied on farming for food supplies.

The long english tradition of figured prominently in the founding fathers' discussion of the ownership of firearms. a) police squads b) target practice c) aristocratic rifle associations d) militias