ecosystem, Biome, biosphere, idk where habitat goes sorry
Answer:
a long rodlike structure that develops dorsal to the gut and ventral to the neural tube. The notochord is composed primarily of a core of glycoproteins that are encased in a sheath of collagen fibers wound into two opposing helices.
Answer:
cells are so small because it is structural functional unit of an organism which can be only seen through microscope
The nervous system, i could be wrong.