Human is the main responsible for the change in the environment. Human activities causes severe damage to the environment. The habitat of different species were destroyed by human for its own purpose. Large number of forest were eliminated for making land suitable for construction and living. Due to vehicles and industries, large amount of carbondioxide is emitted in the atmosphere which contribute in rising the temperature of the earth atmosphere. This global warming change the habitat of different organisms and these organism will die or migrate to other suitable places. Acid rain also occurs due to the emission of CO2, CO and SO2 from vehicles and industries. This acid rain causes adverse effect on the animals, plants and infrastructure or buildings.
The embryo has three germ layers. The ectoderm, mesoderm, and endoderm. The endoderm is the innermost layer. Other than the endocrine glands, the other tissues that develop from the endoderm are the gastrointestinal tract, urinary and auditory system, and the respiratory tract.
