Which statement best describes enzymes? Every enzyme controls many different reactions
The rate of activity of an enzyme might change as pH changes
Temperature changes do not affect enzymes
Enzymes are produced from the building blocks of carbohydrates

The negative change found inside the plasma membrane is created by potassium ions sodium ions hydrogen ions chlorine ions

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 8 options: the cold balloon expands and rises. the warm balloon shrinks and sinks. the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Which greenhouse gas is emitted when burn fossil fuels for energy? a. nitrogen b. oxygen c. carbon dioxide d. helium