Question

which means of communication totals to the combined usage of fax and letters​

Answer 1

EMAIL is the mode  of communication totals to the combined usage of fax and letters​

Explanation:

FAX - is a mode of communication where photo copy of a letter is being sent through a fax machine using telephone

Fax is the telephonic transmission of scanned-in printed material of text or images.

Fax is also called telecopying

Letters is a mode of communication where letters are typed and sent through post,

EMAIL  is a digit communication method used through internet where one can send e-letters . type letters through e-mail.

These letters / email reaches to other person immediately.

A document of image / text can be scanned and attached with the Email which will  do the equivalence work of fax.

Hence EMAIL communication totals to the combined usage of fax and letters