Which of the following is NOT a part of the endomembrane system? MCQ with Answer and Explanation

Explanation:
The epidermis is the avascular, outermost layer of skin, composed mainly of keratinized stratified squamous epithelium. It provides a waterproof barrier and creates skin tone via melanocytes. The dermis is below, containing vessels and nerves, hypodermis is subcutaneous fat, endodermis is a root layer in plants.

Explanation:
Ethylene (C₂H₄) is a gaseous hormone that promotes fruit ripening, senescence, and abscission. It is the only gaseous plant hormone.

Explanation:
Photorespiration is a wasteful pathway that occurs when RuBisCO fixes O2 instead of CO2, producing phosphoglycolate. This 2-carbon compound is metabolized through a complex pathway involving three organelles: it is processed in the peroxisome, then the mitochondria, and finally returns to the chloroplast. This process consumes ATP and releases CO2 without producing any sugar.