The appropriate answer is d. gases such as carbon dioxide and methane. These gases are known as greenhouse gases and they trap heat in the form of infrared radiation. Without this effect the earth would be 30 degrees cooler. Nitrogen dioxide and sulfur dioxide are examples of other greenhouse gases. An increase in the volume of these gases is responsible for present day global warming that is causing a change in the the earth's climate.
Mutualism is relationship that is beneficial to both organisms involved. The relationship between a plant and a bacterium called a mutualism because both of them help each other. Bacteria are involved in increasing the fertility of the soil by fixing atmospheric nitrogen and thus provide plant with nitrogen. In return, the bacteria make their homes in what usually become nitrogen "nodules" along plant roots. The plant gets food, the bacteria gets shelter, everybody wins.
A river flowing<span> across a wide flood plain begins to </span>form<span> loop like bends </span>called<span>. meanders.</span>
