A trapezoid is a type of quadrilateral that has an opposite pair of parallel sides; at lest, that definition seems pretty accurate to me.
Geography uses other subject in it's studies. Very close to geography are geophysics and geology. Geophysics studies quantitatively physical phenomena of the planet Earth, geology studies composition of soil rocks and their development through history. Geography uses biology, statistics, mathematics and other subjects in order to better describe the Earth.
The correct answer is - A. Devonian.
The Devonian is one of the seven periods of the Paleozoic Era. It lasted for 50 million years, from 410 million years ago until 360 million years ago. It is the period in which the first insects evolved, the first seeded plants, as well as the first land vertebrates. This period came after the Silurian period, and was followed by the Mississippian period.
