Answer:
chemical composition,cells, tissues,organs,organ systems,organism.
Answer:
Vertebrae
Explanation:
both birds and reptiles have a backbone or a <em>vertabrae. </em>therefore they are Vertebrates.
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Answer:
Explanation:
some gases prevent the escape of heat from the earth.There will be an increase in the percentage of such gases would cause the average temperatures to increase world wide.This is known as greenhouse effect.Carbon dioxide is one of the green house gases.An increase in the carbon dioxide content in the atmosphere woul cause more heat to be retained by the atmosphere and lead to global warming.
The promise of jobs and prosperity, among other factors, pulls people to cities. Half of the global population already lives in cities, and by 2050 two-thirds of the world's people are expected to live in urban areas. But in cities two of the most pressing problems facing the world today also come together: poverty and environmental degradation.