A craton is a large, stable portion of Earth's lithosphere that makes up part of continent. The Kaapvaal craton in Africa is one of five ancient cratons left from the
Precambrian era. The rock has remained tectonically stable since its formation 3.6
billion to 2 billion years ago. What do you think the term "tectonically stable" means?
you think this rock formation is important to understanding the history of Earth?
Do you think studying ancient rock formations such as the Kaapvaal craton can teach
scientists not only about Earth's past but also its future? Why or why not?

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.

c. establishing proper sleep hygiene