Please answer these, id really appreciate it

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

The mantle is made up of which structural zones?

Which statement is true if the refractive index of medium a is greater than that of medium b? a. total internal reflection is possible when light travels from air to medium b to medium a. b. total internal reflection is possible when light travels from medium a to medium b. c. total internal reflection is possible when light travels from medium b to medium a. d. total internal reflection is possible when light travels from air to medium a. e. total internal reflection is possible when light travels from air to medium b.