Which organelle is called the 'kitchen of the cell'? MCQ with Answer and Explanation

Explanation:
The Casparian strip is a waterproof band of suberin and lignin found in the radial and transverse cell walls of the endodermis (the innermost layer of the cortex) in plant roots. It acts as a barrier to the passive flow of water and dissolved minerals through the cell walls (the apoplastic pathway). This forces water and solutes to cross the selectively permeable plasma membrane and enter the symplastic pathway, allowing the plant to control and filter what enters the vascular cylinder (stele).

Explanation:
Lateral meristems—vascular cambium and cork cambium—are responsible for secondary growth, increasing the girth (diameter) of dicot stems and roots. Apical meristem at root and shoot tips causes primary growth in length. Intercalary meristem at nodes helps in elongation in grasses. Epidermis is a protective outer layer. Secondary growth is absent in most monocots due to lack of vascular cambium.

Explanation:
The 'ozone hole' is a severe, seasonal thinning of the stratospheric ozone layer that occurs most prominently over the Antarctic region during the Southern Hemisphere's spring (September to November). This is due to the unique meteorological conditions in the Antarctic stratosphere, including the formation of Polar Stratospheric Clouds (PSCs) during the dark, cold winter, which provide surfaces for chemical reactions that release active chlorine from CFCs, rapidly destroying ozone when sunlight returns.