Which are the first organisms to start the process of primary succession

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

During endocytosis, cells expel what they don't need take in what they need shrink due to loss of water

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere