J.J. Thomson discovered the electron by noticing that a beam of particles could be influenced by an electric or magnetic force.. That is option B.
<h3>What is an electron?</h3>
An electron can be defined as the part of an atom that is negatively charged and is found revolving round the nucleus of an atom.
J.J. Thomson was the scientist that discovered electrons through subjecting two oppositely-charged electric plates around the cathode ray.
He noticed that the particles where deflected by both the magnetic and electric fields.
Learn more about cathode rays here:
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Answer : The volume of a sample of 4.00 mol of copper is 
Explanation :
First we have to calculate the mass of copper.


Now we have to calculate the volume of copper.
Formula used :

Now put all the given values in this formula, we get:


Conversion used :

Therefore, the volume of a sample of 4.00 mol of copper is 
Answer:
Explanation:
The explanation is given in the attached document.
<span>The side of the worm that faces up when placed in the
tray for dissection is the smoother side.
</span>You can observe the organs of these tiny creatures by dissecting a preserved earthworm<span>. In dissecting
a worm, </span><span>lay the worm on your </span>dissecting
tray<span> <span>with its dorsal side facing up.</span></span>