What is a yellowish-green coloration in normally green tissues such as leaves?

Chlorosis is the correct answer because it refers to a condition where there is a loss of the green pigment chlorophyll in plant tissues, resulting in a yellowish-green color. Option A, etiolation, refers to the process of plants becoming pale and weak due to a lack of sunlight. Option B, blight, is a general term for plant diseases that often cause discoloration, but it is not specific to yellowish-green coloration. Option D, wilting, refers to plants losing rigidity due to lack of water, and does not necessarily involve color changes.