There are two questions about solidworks.
1. why is it good practice to fully define
sketchgeometry?
2. describe what happens if you do not select a planeprior to
clicking on the sketch icon when creating a sketch.

1. It is a good practice to fully define a sketch to avoid having erroneous dimensions on the faces of a solid, this avoids that when it is required to make an assembly with the drawn part appear assembly errors.

2. The 2D sketch should always be done on a plane, so solidworks would ask you to select a plane on which you want to make the sketch, on the other hand, if it is a 3D sketch, solidworks allows you to do it without the need for Select any plane.

energy can cross the boundaries of a closed system in the form of heat and mass

explanation:

it was a fall down when it happens

explanation: