Answer:
A. carbon and boron
Explanation:
Carbon and boron is not an alloy.
An allow forms between metals and metals using their huge electron could.
Carbon is a non-metal, boron is a also a non-metal
Two non-metals combining together does not make an alloy.
Iron, nickel, aluminum are all metals.
Inconsistent. You should take three readings at least.
Do you have a picture then I could determine 1 millimeter
Answer:
The charge density in the system is 
Explanation:
To solve this problem it is necessary to keep in mind the concepts related to current and voltage through the density of electrons in a given area, considering their respective charge.
Our data given correspond to:

We need to asume here the number of free electrons in a copper conductor, at which is generally of 
The equation to find the current is

Where
I =Current
V=Velocity
A = Cross-Section Area
e= Charge for a electron
n= Number of free electrons
Then replacing,


Now to find the linear charge density, we know that

Where:
I: current intensity
Q: total electric charges
t: time in which electrical charges circulate through the conductor
And also that the velocity is given in proportion with length and time,

The charge density is defined as

Replacing our values


Therefore the charge density in the system is 
Answer: Objective Observations
Explanation: The first step in the Scientific Method is to make objective observations. These observations are based on specific events that have already happened and can be verified by others as true or false