Geologists generally agree that earth is about 100 million years old. about 4.55 billion years old. about 6,000 years old. as old as the hills and twice as dusty.

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.

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?

What class of levers is shown in this image?