Since you didn't have any extra information about the question I'll be presenting an example from my own textbooks that I've used.
An example of a direct observation is listening to a cricket chirp at night, and counting the number of chirps per minute.
Direct Observation is where the evaulator watches the subject in their usual habitat without disrupting or altering it.
Answer:
B
Explanation:
Asteroid - A rock that rvolves arounf the sun / star.
Moon - A natural satillite that revolves around earth/ planet.
Molar mass SiO2 = 28 + 32 = 60
<span>so moles sand = 3.4 x 10-7 / 60</span>
<span>In a salt solution (a solution of water (H2O) and Salt, chemical formula NaCl), the positively charged Hydrogen atoms from water form bonds with the negatively charged Chloride atoms of Salt (which is the formulate NaCl), and the negatively charged oxygen atom of water (one atom per water molecule) form a bond with the positively charged Sodium ions (Na) of salt.</span>
Answer:

Explanation:
The pH of a solution can be found by using the formula
![pH = - log [ {H}^{+} ]](https://tex.z-dn.net/?f=pH%20%3D%20-%20log%20%5B%20%7BH%7D%5E%7B%2B%7D%20%5D)
Since we are finding the H+ ions we find the antilog of the pH
So we have

We have the final answer as

Hope this helps you