Answer:
Migration boosts the working-age population. Migrants arrive with skills and contribute to human capital development of receiving countries. Migrants also contribute to technological progress. Understanding these impacts is important if our societies are to usefully debate the role of migration
<u>Answer:</u>
<em>Anytime observations need to be clarified. When an unusual condition need to be shown for later reference.</em>
<u>Explanation:</u>
Instead of just recording the data the is sometimes important to be sketched out as the data observed is needed to be clarified and also sometimes there is an unusual condition that occurs and hence, it is important to sketch it so that it can be used for later reference.
<em>Therefore, when we are aware of the situation we need not sketch the data.</em>
