What causes changes in the Geological Time Scale?A. Increased rock sediments B. Evidence of prehistoric life
C. Changes to biodiversity

Please explain!!!

What can you increase the strength of an electromagnet by

Two cans on a sunny window one black and the other white construct and explanation of the effect of sun will have on both cans over a two hour period?

Which of the following can enter and exit a closed system? a. matter and energy b. neither energy nor matter c. matter but not energy d. enrgy but not matter