Explanation

Absorbance (A) is a logarithmic ratio of incident to transmitted light; hence, it is unitless.

In the Beer-Lambert law:

A=ε⋅C⋅L, only ε (molar absorptivity) carries units to balance the equation.

Explanation

Secondary syphilis commonly presents with fever, skin rashes (especially on palms and soles), and joint pain.

It occurs weeks after the primary sore and indicates systemic spread of the infection.

Explanation

A virus consists of a protein coat (capsid) that surrounds its genetic material (DNA or RNA).

It lacks cellular structures.

It is not considered a complete cell.

Explanation

"Old" starts with a vowel sound, so we use "an" before it.

Correct sentence: "Is your mother working in an old office building?"

Explanation

A light microscope can magnify up to 1000x (typical maximum), resolving structures as small as 0.2 micrometers.

This is ~1000x sharper than the naked eye (which resolves ~0.2 mm).

Explanation

Add and Added show a change from present to past tense.

Say and Said also represent present to past tense, matching the same pattern.

Explanation

Polychromatic light contains multiple wavelengths or colors of radiation.

It is the opposite of monochromatic light, which has only a single wavelength.

Explanation

Improve means بہتر بنائیں

Refine means بہتر کریں

Explanation

Cling means to hold on tightly.

Cede means to let go or surrender.

Cling means مضبوطی سے تھامنے کے لئے

Cede means جانے یا ہتھیار ڈالنے کے لئے

Explanation

Equisetum is commonly called horse-tail due to its brush-like appearance.

It belongs to Pteridophytes.

It is a living fossil.

It is found near wetlands.