Plant Reproduction and Germination

Vivipary means that seed remains attached to the plant even during germination. It is an undesirable character for annual crops as they are not able to store under normal condition for coming years.

Sexual reproduction involves the formation of haploid gametes. The gametes are produced by a specialised type of cell division called meiosis. The meiosis is a special type of division because it is reductional division and it involves crossing over. The crossing over involves the exchange of chromosomal segments between non-sister chromatids of a homologous pair of chromosome. The crossing over results in new genetic combinations. The rearrangement of genetic material every time crossing over occurs produces new combinations thus leading to the generation of variations in a sexually reproducing population.

Vegetative propagation is a form of asexual reproduction where plants grow from vegetative parts like stems, roots, or leaves without seeds. Since asexual reproduction is the broader category that includes vegetative propagation, both options A and C are correct.

Scattering of seeds ensures the spread of species over the maximum area which protects it and it also prevents the growth of the same plant at one place and reduces the competition of food and other resources hence reduces competition and over-crowding.

As seeds mature, they undergo dehydration. Enzyme activity is significantly reduced or stopped when the moisture content drops to a very low level, typically around 10-20 percent, to induce dormancy.

Pea and castor are dicots (2 cotyledons), while maize is a monocot (1 cotyledon). Thus, the sequence is 2, 2, and 1.

Coleoptile and coleorhiza are protective sheaths found in monocot seeds, covering the plumule and radicle respectively (e.g., maize and wheat). Gram is a dicot seed and therefore lacks these structures, possessing instead typical dicot features like cotyledons and a direct-emerging radicle.

Seed coat is not thin in coconut. The fruit is an indehiscent fruit in which an outer fleshy part-exocarp or skin and mesocarp or flesh surrounds a shell of hardened endocarp with a seed inside. These fruits usually develop from a single carpel and mostly from flowers with superior ovaries. The definitive characteristic of a drupe is that the hard, lignified stone is derived from the ovary wall of the flower. The coconut is  a drupe, but the mesocarp is fibrous or dry, so this type of fruit is classified as a simple dry fruit, fibrous drupe. 
Therefore, the correct answer is option A.

The seed is endospermic in Ricinus. A characteristic of castor seed is the presenee of caruncle which develops from peduncle. The fruit is a spiny, greenish capsule containing large, oval, shiny, bean-like, highly poisonous seeds with variable brownish mottling.
A capsule is a type of simple, dry fruit produced by many species of flowering plants. A capsule is a structure composed of two or more carpels. Castor seeds have a warty appendage called as the caruncle, which is a type of elaiosome. The seeds are endospermic or albuminous where the embryo is embedded in the endosperm and nucellus, which the seedling will use upon germination. 
Therefore, the correct answer is option A.

Radicle is the first part of a seedling to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant and grows downward in the soil.
Plumule is the young shoot of  a plant embryo above the cotyledons, consisiting of the epicotyl and often of immature leaves.
Cotyledon is the significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling.
Ovule is the structure that gives rise to and contains female reproductive cells.
Thus, the correct answer is option (B), 'Plumule'.

Orchid seeds are small, light and contain little food reserves. A single seed capsule may contain1,500 to 3,000,000 seeds. Orchid seeds are small, dry, dusty and weighing as little as 0.004 mg.
So, the correct answer is 'small and light'

Seeds germinate in the presence of warmth, moisture and air. No light is needed for germination. Seeds generally contain starch as food supply. So, light is not needed for food production also during germination.

The pericarp of the maize is fused with the seed coat known caryopsis. The entire kernel is referred to as the seed.
Therefore, the correct answer is option A.

Viviparous plants produce seeds that germinate before they detach from the parent plant. In Rhizophora (mangroves), the seed germinates and develops into the seedling when it still attached to the parent plant
So, the correct answer is 'Rhizophora'

In monocot seeds like wheat or maize, the scutellum is a modified cotyledon that serves to absorb nutrients from the endosperm for the developing embryo.