Which of the following quantities for an object should be known to calculate its density? (5 points) The space it occupies The heat present in it The force of gravity acting on the object How long it takes for an object to travel a certain distance

In the analysis of hair and fiber samples, which does a compound comparison microscope allow for that a conventional compound microscope does not? a. simultaneous observation b. polarization c. fluorescence d. higher magnification

What effect might melting sea ice have for people who live in coastal areas?

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