Your slide is in focus but you cannot see anything, what maybe the possible problem​

The correct answer would be - using a lens that is too high powered and thus you may be too focused on the specimen.

Explanation:

The possible scenario for this case where the slide is in focus but can not see anything could be either specimen is not under the lense or too focused on the specimen by using a very high-powered lens.

In a very high-powered lens, the lens becomes over-focused and the specimen does not look in the field of view of the lens, in such case, an individual should ower the power of lense.

hope this !

69 is the correct math for the amino acids