Question

Primary cell wall formed by 
(a) Intussusception
(b) Apposition
(c) Intussusception & lignification 
(d) Mineralization 

Answer 1

Hint:The term functionally is different between both plants and humans. In plants, it refers to the cell wall formation but in humans, it is a disease that causes an intestinal obstruction (blockage) in which one part of the intestine 'telescopes' within another. It typically takes place at the junction of the small and large intestines and causes serious intestinal damage.

Complete answer:
Intussusception is cell wall development by the deposition of cellulose. The plant cell wall is a result of protoplasmic activity and its formation starts in the higher plants, immediately after nuclear division, with the formation of the cell plate. This thin cell plate rapidly acquires the shape of a primary cell wall, defined as the structure that encloses the protoplasts during the enlargement of the cell. When the cell enlargement cycle is over the cell wall becomes thickened to transform into the secondary wall. The secondary wall is known to be the plant's structural component.
Intussusception occurs in the primary cell wall as another cell wall begins to develop in the already developed cell wall fibril. Usually, the primary wall expands in such a way that polysaccharides, cellulose, and other pectins are distributed through the expanding wall (expansion is due to turgor pressure) .
In intussusception two hypotheses exist,
- The microfibrils are interwoven and the materials deposit in these gaps.
- Turgor pressure produces a gap in the primary wall and cellulose and pectins fill those gaps.
Additional information
Primary cell wall formation
Cytokinesis occurs by the creation of cell plates in terrestrial plants. This process involves the delivery of the Golgi- derived and endosomal vesicles taking the cell wall and cell membrane constituents, followed by the fusion of these vesicles within this plate. Following the development of an early
tubulo- vesicular (also called ER- Golgi intermediate compartment) network in the center of the cell, the initially labile cell plate consolidates into a tubular network, and finally a fenestrated sheet. The cell plate expands outward from the center of the cell to the parental plasma membrane and fuses with it, thereby completing the cell division. The development and growth of the cell plate depend on the phragmoplast, which is needed for proper targeting of the cell plate of Golgi- derived vesicles. The phragmoplast disassembles as the cell plate matures in the cell’s center and new elements are added to its outside. This process leads to the steady expansion of the phragmoplast and at the same time it
continuously retargets the Golgi derived vesicles to the expanding edge of the cell plate. This event not only marks the separation of the two daughter cells but also initiates a series of biochemical modifications that turn the callose- rich, flexible cell plate into a rigid primary cell wall rich in cellulose.
So, the correct answer is ‘Intussusception’.

Note: Cellulose is an essential structural component of the primary cell wall of green plants, many algae types, and the oomycetes. It is secreted by certain bacterial organisms to form biofilms. Cellulose's chemical composition parallels that of starch, but cellulose, unlike starch, is highly rigid. This stiffness gives the plant body great strength and protects the interiors of plant cells. Animal cells lack cell walls and thus do not have rigidity.