I have a question my teacher today in biology said " you think you are moving your hand by yourself, but it's actually your brain sending commands to your muscles so they can move." So I wondered.. is my brain sending commands so I can think, or am I thinking whenever I have a desire to? (Not a trick question; My friend thinks this is a trick question lol).

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.

20 the compound al(nh3)2 has atoms of nitrogen.

There are only about 250,000 known fossil species. true or false