<u>Answer:</u> Erosion
<em>The process in which there is a wearing down on the surface on the earth which goes through the erosion is called gradation.</em>
<u>Explanation:</u>
There is a certain force which is the cause for the <em>formation of earth’s surface and that force is called as endogenic forces. </em>
There may come up a question about how the <em>surface of the earth</em> is not even, the reason is due to exogenic process failing to even out <em>the variation of the land.</em>
Anaerobic respiration<span> is in muscles. Glucose is not completely broken down, so much less energy is released than during </span>aerobic respiration<span>. There is a build-up of lactic acid in the muscles during vigorous exercise. The lactic acid needs to be oxidised to carbon dioxide and water later.</span>
Sternal angle marks the joint between the sternum and the 2nd rib.
Option E.
<h3><u>Explanation:</u></h3>
Sternum is the breast bone which is a dorsi ventrally flattened bone present in thorax of human. It gives the support for the ribs where the ribs join. A sternum has three parts - Manubrium sterni, body of sternum and the xyphoid process.
The sternum has attachments of a total of 10 ribs and clavicle. The clavicle and the first rib joins in the Manubrium sterni, and the 3rd to 10th rib joins in the body of sternum. The 2nd rib joins in a facet which is partly in Manubrium sterni and partly in body of sternum. This place id also called the sternal angle. So the sternal angle marks the joint of 2nd rib to sternum.
Scientific validity is the applicability of a conclusion drawn in the context of a scientific experiment to the world at large.