Umm either one? We have nothing to base that one except belief. Yes, we know there were ice ages, but we don't know how small fluctuations in climate happened, nor why.
Originally Posted by Judee
1. something that is contemplated, devised, or planned; plan; scheme.
2. a large or major undertaking, especially one involving considerable money, personnel, and equipment.
3. a specific task of investigation, especially in scholarship.
4. to propose, contemplate, or plan.
5. to throw, cast, or impel forward or onward.
6. to set forth or calculate (some future thing).
7. to extend or protrude beyond something else.
8. to use one's voice forcefully enough to be heard at a distance, as in a theater.
9. to produce a clear impression of one's thoughts, personality, role, etc.