Small fragments of orbiting bodies that have landed on Earth are known as meteorites. If the fragments are still orbiting earth are known as meteoroids. They are not called meteorites until they enter Earth's atmosphere. Once a meteor enters Earth's atmosphere it will begin to burn up. It may burn up completely or lose most of its size by the time is lands on Earth's surface.
Germ layer is a primary layer of cells found in the embryo. The three primary germ layers that generate most of the cells in the developing mammalian forelimb are ectoderm, mesoderm and endoderm.
Ectoderm forms the outer component of a mammalian body such as skin, hair, etc. Endoderm forms the inner layer that comprises of the linings of digestive system, lungs and thyroid. Mesoderm is the middle layer that forms the skeletal system, heart, etc.
Neural tube is generated by the inward folding of the ectoderm. This process is called neurulation. Ectoderm also forms neural crest.
Once during mitosis and twice during meiosis.
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Answer:
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