Hi,
It is <u>Scholastic Assessment Test</u><u>.</u> It is especially common in the US and Canada colleges and universities. It is a written paper-pencil test and helps evaluate the language and mathematical reasoning skills of the applicants.
<u>(</u><u>By</u><u> </u><u>Benjemin</u><u>)</u>
The statement that describes the 3d, 4s, and 4p orbitals of arsenic (as) based on its electronic configuration and position in the periodic table is; The 3d and 4s orbitals are completely filled, and the 4p orbital is partially filled.
The electronic configuration of arsenic is given as; 1s² 2s² 2p^(6) 3s² 3p^(6) 4s² 3d^(10) 4p³.
Now we can see that in that electronic configuration the orbitals are, s, p and D.
Now, the maximum electrons for each of the 3 orbitals are;
Maximum electrons for d orbital = 10 electrons
Maximum electrons for s orbital = 2 electrons
Maximum electrons for p orbital = 6 electrons.
Now, when we compare the maximum number of electrons for each orbital to the ones in electron configuration of arsenic, it is clear from the last 3 orbitals that the 3d and 4s orbitals are completely filled while the 4p orbital is half filled or partially filled.
Read more about electronic configuration at: brainly.com/question/24258336
The correct answer is - B) the water quality of the stream.
By studying the fish populations and their well being, the watersheds, as well as the composition of the water, the scientists are trying to keep track of the situation of the quality of the water in the stream.
The fish populations, their activity, well being, are always a nice indicator about the water quality, as they live in it and are directly effected by any negative changes in the water quality.
The watersheds can also show a partial picture of the quality of the water in the streams, and that is because the water passes through them before entering the stream itself, so a clean and healthy watershed, often means good quality of the water.
The most relevant indicator of the quality of the water in the stream is still the testing of the water itself, where the water composition can be examined in detail thus to be determined its condition.
