Meaning of "as" and present perfect

Hi, there

Please consider the following questions:

1. Without him, using electricity as we do today would be impossible.

(1) You can eat as you want.
(2) They did as I had asked.
(3) As I drink milk, I eat cookies.
(4) He is fat, as he eats too much.
(5) As my sister grows, she becomes pretty.

2. People today have begun to learn more about Tesla.
He is now known as the father of AC electrical systems.

(1) She has lived in this town since she was ten.
(2) I have lost my book at library.
(3) I have just finished my homework.
(4) They have already eaten dinner.
(5) He has never been to Japan.

In question 1, the meaning of "as" I think is "like" but unfortunately I don't have the anwer with me so I have no idea what would be the answer. Aand I really would like to know the meaning of "as" for each option.

Finally, Q2 asks about present perfect which is pretty ambiguous for me. Could you paraphrase the question 2 and the options for me?

Thanks in advance