True. The crust of the Earth has some permanent magnetization, and the Earth's core generates its own magnetic field, sustaining the main part of the field we measure at the surface. So we could say that the Earth is, therefore, a "magnet."
Out of the choices given, one adaptation that is unique to marine mammals is they can slow their own heartbeat down.
Your answer should be a crack in the topmost section of a glacier
Acids are substances that provide hydrogen ions (H+) and lower pH, whereas bases provide hydroxide ions (OH–) and raise pH. The stronger the acid, the more readily it donates H+. For example, hydrochloric acid and lemon juice are very acidic and readily give up H+ when added to water. ( source : https://courses.lumenlearning.com/wmopen-nmbiology1/chapter/the-ph-scale/ )