NEET Practice Questions (MCQs) with Answers & Solutions

The context explains redifferentiation: 'While doing so, such meristems/tissues are able to divide and produce cells that once again lose the capacity to divide but mature to perform specific functions, i.e., get redifferentiated.'

The context mentions: 'The final structure at maturity of a cell/tissue is also determined by the location of the cell within.'

Figure 13.8 shows 'Cell Division', 'Expansion (Elongation)', 'Differentiation', 'Maturation', 'Senescence', 'Death', and 'Plasmatic growth'. 'Regrowing' is not listed as a phase.

The text states: 'Plants follow different pathways in response to environment or phases of life to form different kinds of structures. This ability is called plasticity, e.g., heterophylly in cotton, coriander and larkspur.' The question asks for the general ability, which is plasticity, and heterophylly is an example of it.

The text explicitly states: 'This phenomenon of heterophylly is an example of plasticity.' And also, 'Plant exhibit plasticity in development.'

The context from page 172 clearly states: 'Now, we may say that even differentiation in plants is open, because cells/tissues arising out of the same meristem have different structures at maturity.'

The text on page 172 states: 'For example, to form a tracheary element, the cells would lose their protoplasm. They also develop a very strong, elastic, lignocellulosic secondary cell walls, to carry water to long distances even under extreme tension.'

On page 173, it is stated: 'A differentiated cell may dedifferentiate and then redifferentiate. Since differentiation in plants is open, the development could also be flexible, i.e., the development is the sum of growth and differentiation. Plant exhibit plasticity in development.' This directly links the ability to dedifferentiate and redifferentiate to the flexibility/plasticity of plant development.

The prompt asks: 'What would you call the parenchyma cells that are made to divide under controlled laboratory conditions during plant tissue culture?' These cells are originally differentiated parenchyma cells, and when they are induced to divide, they are undergoing dedifferentiation, regaining their cell division capacity. The product of this process, if it forms an undifferentiated mass, is often called callus, which is composed of dedifferentiated cells.

According to the NCERT text, 'When light travels from an optically denser medium to a rarer medium at the interface, it is partly reflected back into the same medium and partly refracted to the second medium. This reflection is called the internal reflection.' For total internal reflection, light must travel from a denser to a rarer medium, and the angle of incidence must exceed the critical angle.