What is a substrate control? why is it done?

An uncontaminated sample is known as a substrate control.  

Explanation:

During the investigation of a crime scene, the forensic scientist collects a sample. This sample helps the forensic scientist to have a better understanding about it.  

A substrate control comprises of uncontaminated surface material near a region where physical proof has been saved. This example is to be utilized to guarantee that the surface on which an example has been stored doesn't meddle with research center tests.

Also, this sample ensures that the surface where the sample has been collected does not interfere with the lab test. The substrate controls enable the background reading about the stained sample.

answer: the figure is attached herewith.

step-by-step explanation:   we are given to sketch a unit circle and label the terminal points corresponding to

in the attached figure, we have drawn a unit circle, with centre at o(0,0) and radius 1 unit. we have labelled the points a, b, c, d and e corresponding to the angles below

∠aox = 60°,

∠box = 120°,

∠cox = 180°,

∠dox = 240°,

∠eox = 300°.

and the coordinates are a(0.5,1), b(-0.5,1), c(-1,0), d(-0.5,-1) and e(0.5,-1).

thus, the answer is complete.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.