Botany and Plant Science

Kranz anatomy is found in leaves of $C _{4}$ plants. The $C _{4}$ pathway requires the presence of two types of cells i.e., mesophyll cells and bundle sheath cells. The particularly large cells around the vascular bundles of $C _{4}$ plants are called bundle sheath cells, these cells may form several layers around the vascular bundles, they are characterized by having a large number of chloroplasts, grana are absent, thick walls impervious to gaseous exchange and no extracellular spaces. This special anatomy of leaves of the $C _{4}$ plants is called Kranz anatomy. 'Kranz' means wreath and is a reflection of the arrangement of cells.

CAM plants are usually the succulents (eg : cacti, agave) as they are efficient at storing water due to the climates they live in i.e., dry and arid. The leaves of succulent plants are thick, contains moisture and have a coat of wax to reduce evaporation. During the day, the plants close their stoma to prevent the loss of water and open it at night to absorb the carbon dioxide from the surrounding atmosphere. The carbon dioxide is later converted into malate, which is used in the process of photosynthesis (via the calvin cycle) when the daylight returns.

• Kranz anatomy is a special structure of leaves in C4 PLANTS e.g. maize, sugarcane, sorghum, and millets.
  
• Mustard and Spinach belongs to C3 plants.
  
• Tulip is an example of a CAM plant. 

A) Phanerogams are seed bearing plants like Gymnosperms and Angiosperms. They have prominent stomata.

• $C _4$ photosynthesis incorporates novel leaf anatomy, metabolic specializations, and modified gene expression.
• Plants that utilize this pathway typically possess a distinctive Kranz leaf anatomy, consisting of two photosynthetic cell types.
• Their vascular bundles are surrounded by two rings of cells; the inner ring, called bundle sheath cells, contains starch-rich chloroplasts lacking grana, which differ from those in mesophyll cells present as the outer ring.
• This structural framework allows for the compartmentalization and functional separation of two sets of carboxylation and decarboxylation reactions.
  Hence, the correct answer is C.

Papaya plant is a dioecious plant. It prevents both autogamy and geitonogamy, which is a method of self pollination.

The transfer of pollen from an anther of a flower of one plant to a stigma of a flower of another plant of the same species by the action of wind, insects etc is known as cross pollination. 

Heterostyly is a form of polymorphism. In this condition, styles are of different lengths relative to the stamens in flowers. This reduces self pollination and promotes cross pollination. Primrose plants shows heterostyly.

Herkogamy - common strategy employed by hermaphroditic angiosperms to reduce sexual interference between male and female function. It differs from other such strategies by supplying a spatial separation of the anthers and stigma.

Herkogamy is a probable strategy applied by hermaphroditic angiosperms to reduce sexual interference between male and female function. It varies from other such strategies by supplying a spatial parting of the anthers and stigma.

Heterostyly is referring to the condition of having styles of different lengths, These are relative to the stamens in the flowers of various individual plants for reducing self-fertilization.

Dichogamy is the condition in which the male and female reproductive organs of the flower mature at different times to ensure that self-fertilization does not occur.

Cleistogamy refers to the self-fertilization which occurs within a permanently closed flower.

So option B is correct.

In heterostyly condition , stamens style and stigma are of different heights e.g., Primula , Oxalis , Linum etc .

Cleistogamy is not a device to promote cross-pollination as the flowers remain closed and they promote self-pollination. For example, Balsam, Oxalis and Viola anthers dehisce inside closed flowers. 

In some plants when the stigma receives pollen from the same flower as well as from the other flower simultaneously, the foreign pollen germinates vigorously and fertilize the ovule.