My work is as simple as a lock and key yet without my shape, my work isn't as good as can be what am i?

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.

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Adult wasps sting caterpillars and inject their eggs into the caterpillars. the larvae feed on the caterpillars, leading to the death of the caterpillars. what kind of a relationship exists between the wasps and the caterpillars? a. the adult wasps are parasites to the caterpillars. b. the caterpillars are parasites to the wasps. c. the adult wasps are commensals, and the caterpillars are hosts. d. the caterpillars are commensals, and the adult wasps are hosts.