It's the "objective" lens ... the big one in the front.
Do not forget that mass = <span>volume x density
</span>Mass of 1 cm^3 = Density[/tex]

Then eventually we can find <span>mass of 5 cm^3 : =
</span>

So the answer is D
<span>And that's it. I'm sure it will help.</span>
Answer: The 1st one is B. I'm pretty sure the 2nd one is A. and the 3rd one is D.
Explanation: I hope this helped, although I'm not sure for the second one
I think it’s D sorry If I’m wrong