The Maastrichtian age was the last part of the Cretaceous period , about 71 to 65 million years ago, at the very end of the Mesozoic Era . The Earth's magnetic field is aligned with the north and south poles, and has reversed many times during geologic history. A fossil's magnetic orientation can give clues to its date.
Mangroves are tropical evergreen trees and shrubs.
They live near the shore in tropical marshes and tidal shores with their adventitious roots in the salt water. The margins of a leaf are its edges, which very from plant to plant. The meristem is a group of plant cells that can divide indefinitely. The meristem provides new cells for the plant. Mesic soil is exellent for farming.