Evidence unearthed by scientists supports the conclusion that about 65 million years ago a large object from space crashed into an area north of what is now the Yucatan Peninsula of Mexico. The impact threw huge amounts of dust into the atmosphere which spread across Earth's
sky, blocking the sunlight. At about the same time
dinosaurs, and many other forms of life in all regions of Earth, became extinct.
Describe how this event could have caused herbivorous and carnivorous organisms to become extinct.

Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? a. the chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced. b. the chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production c. free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone. d. chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone select the best answer from the choices provided

Amarine ecologist has constructed the conceptual model shown in the diagram. what predictions can be made from using this model? where the tertiary consumers get their energy how often primary producers are able to reproduce when bacteria and fungi initiate the process of decomposition whether other secondary consumers are present

Identify two examples of chemical reactions that you have encountered during the last week. identify an exothermic and endothermic reaction. explain.