Litmus paper is used to detect the presence of an acid or a base. Red litmus paper turns blue when a base is detected, and blue litmus paper turns red when acid is detected. In this example, litmus paper is acting as an A. Indicator
B. Chemical Reaction
C. characteristic
D. Benedict's test

A: Indicator

Explanation:

An indicator is a substance that reacts when exposed to other acidic or alkaline substances, which is exactly what litmus paper does, so litmus paper is acting as an indicator.

Indicator

Explanation:

because it indicate about the solution is it basic or acidic.

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"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."