NEET Practice Questions (MCQs) with Answers & Solutions

The cuticle is a waxy layer present on the surface of both leaves and stems. It serves to reduce water loss by evaporation and provides a barrier against pathogens. It is not present on roots as roots are responsible for water absorption.

Companion cells are specialized parenchyma cells found in the phloem of flowering plants. They are closely associated with sieve tube elements and help in the transport of sugars and other nutrients.

Sieve tube elements are characterized by the absence of a nucleus at maturity, which allows for more efficient transport of nutrients. The presence of companion cells helps to maintain the metabolic functions that the sieve tube elements cannot perform due to the absence of a nucleus.

Xylem parenchyma is the only living component in the xylem tissue. It plays a crucial role in the storage of nutrients and water, as well as the lateral transport of water and minerals.

Safranin is a biological stain used for coloring lignified cells. Lignin is a complex organic polymer found in the cell walls of many plants, making them rigid and woody. Safranin stains these cells red, which helps in identifying lignified tissues under a microscope.

Radial vascular bundles are typically found in roots. In radial vascular bundles, the xylem and phloem are arranged in an alternating manner on different radii. This arrangement is common in the roots of dicot and monocot plants, helping in the efficient transport of water, nutrients, and food.

Cucurbita stem shows bicollateral vascular bundles which produce outer and inner phloem but intraxylary phloem is absent. 

The exarch condition of xylem, where the protoxylem is located towards the periphery and metaxylem towards the center, is typically found in roots. This arrangement is essential for the conduction of water and nutrients from the soil to the rest of the plant.

Endodermis is a layer of cells that is typically present in roots and helps in regulating the flow of water and minerals into the vascular tissue. It is usually absent in monocot stems, which lack this specialized layer.