a farmer is using a crop duster to spray chemicals on his crops to kill insects. the chemicals the farmer uses seeps into the soil and drains into the nearby river. how does this effect the animals that live in the river?
a) they swim away.
b) they change color.
c) they get sick or die.
d) the chemicals give them more energy.

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

Identify the electromagnets with poles that are reversed from the electromagnet shown above

Which process transfers heat from inside earth to its surface? convection currents in mantle pulling away of tectonic plates drawing in of tectonic plates convection currents in crust