AP BIOLOGY

Detailed explanation-1: -In rock layers, jellyfish fossils are found lower than trilobite fossils, and trilobite fossils are found lower than ammonite fossils. What can be determined from this information? Jellyfish existed before trilobites and ammonites.

Detailed explanation-2: -The fossils are found in a limestone shale. This shale splits easily into flat sheets, revealing the trilobite fossils. Fossilized trilobites lay nearly flat along the splitting planes of the shale.

Detailed explanation-3: -Their fossilized remains are found in the rugged mountains of western Canada, the rolling plains of eastern Europe, the scorching deserts of northern Africa and the verdant hills of southern China. Indeed, trilobites can be discovered on every continent on earth where Paleozoic outcroppings exist.

Detailed explanation-4: -Trilobites and ammonoids are among the best studied and most famous groups of fossil marine invertebrates. Great numbers of studies have been conducted on each.