Butter is melted in a pan. which of the following is true about the change?
select one:
a. it is a physical change that absorbs energy.
b. it is a physical change that releases energy.
c. it is a chemical change for which there is no change in energy.
d. it is a chemical change that absorbs energy.

Astudent made a graph plotting the progress of a reaction over time. the student forgot to label the y-axis of the graph. a graph is shown with two graph lines. one graph line starts at a higher position on the y axis and slopes downwards towards the right. the other graph line starts at a lower position on the y axis and slopes upwards towards the right. the two graph lines stop short of intersecting each other and continue as separate lines which gradually become straight and parallel to the x axis. a vertical line is shown at a point where the two graph lines finally became parallel to the x axis. this vertical line is labeled equilibrium. the title on the x axis is time and an arrow pointing towards the right is shown above time. the title on the y axis is left blank. what best explains the label that the student should use on the y-axis? amount, because as the amount of product decreases, the amount of reactant increases over time. reaction rate, because forward and backward reaction become equal at equilibrium. amount, because the amounts of reactants and products become constant after equilibrium is reached. reaction rate, as the rate of forward reaction increases and rate of backward reaction decreases over time.

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?

Which are examples of how technology has advanced scientific understanding.1using hot water to sterilize medical equipment.2transplanting a human organ into another individual.3inserting genes from one sheep into another cell to make a cloneunderstanding the different structures that make up a cell.4examining microorganisms from the deepest parts of the ocean