Answer: Layer a is 500 million years old.
Explanation:
Trilobite is a member of the group of extinct arthropods found as fossils and they can be identified by the three-lobed as well as three segmented forms. These were the marine animals. These were appeared initially in the Cambrian Period. They used to live 542 million years ago so the fossils can be estimated to be aged of 500 above years old. These animals used to dominate in the sea area.
Its the Eccentricity of the earth. (shape of Earth's Orbit around the sun, whether it is more circular or ovular.)
Fire can be accidental or intentional, and it can cause erosion.
The outer layer of the skin covering the exterior body surface<span> of vertebrates ... the primary tissue of higher plants composed of </span>thin<span>-walled </span>cells<span> that remain capable of ... a swelling on a plant stem consisting of overlapping immature </span>leaves<span> or petals ... Older xylem </span>near<span> the center of a woody stem that no longer conducts water.</span>
Answer:B
Explanation: Since there’s more snakes they’ll outweigh the rats and end up eating them until they’re gone unless the snake population decreases
