<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>
Gobi desert; yellow sand; yellow river
Answer:
The answer is B
Explanation:
I am pretty sure, dont take my word for it
These subs are useful in studying the ocean floor, where it is so deep that divers would be crushed by the water pressure. For example, research submersibles are used to study shipwrecks like the RMS Titanic.