Rollin down a backwood, Tennessee byway. One arm on the wheel, holdin my lover, with the other.
<span>So far, astronomers have found more than 500 solar systemsand are discovering new ones every year. Given how many they have found in our own neighborhood of the Milky Way galaxy, scientists estimate that there may be tens of billions of solar systems in our galaxy, perhaps even as many as 100 billion.</span>
<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>
Levees and embankments allow humans to c)settle below river level. A levee is defined as "an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels." This definition can also be used for the term embankment.
