I would have to say (D.) if it's been 150 years.
The correct choice is velocity=distance/time of v=d/t
Less prey means less predatoors
Mars is just a fraction the size of the Earth, so it cooled more rapidly. And as it cooled, its molten iron core hardened. As a result, Mars stopped generating its magnetic shield. And, according to one theory, this left its atmosphere to be scoured away by the solar wind.
