NEET Practice Questions (MCQs) with Answers & Solutions

The chief characteristics of a stem include developing from the plumule, having a positive phototropic nature, and the presence of nodes and internodes. However, the presence of endogenously developed multicellular hair is not a characteristic of the stem.

In ginger, vegetative propagation occurs through rhizome. Rhizomes are stems which grow horizontally under the ground. In ginger, the underground stems are swollen with food reserves. The terminal bud grows upward to produce the flowering shoot and the lateral buds grow out to form new plant.

Plants that produce pneumatophores, i.e. negatively geotropic roots and show vivipary, i.e. germination of seeds inside the fruits are halophyes. These plants are adapted to grow in highly saline areas such as mangroves. Pneumatophores help these plants in respiration as they do not get sufficient oxygen from the soil. On the other hand vivipary aids in perennation. 

The root is covered at the apex by a thimble-like structure called the roat cap. It protects the tender apex of the root as it makes its way through the soil. A few millimetres above the root cap is the region of meristematic activity. The cells of this region are very small, thin-walled and with dense protoplasm. They divide repeatedly. The cell proximal this region undergo rapid elongation and enlargement and are reponsible for the growth of the root in length. This region is called the region of elongation. The cells of the elongation zone gradually diferentiate and mature. Hence, this zone, region of maturation. From this region, some of the epidermal cells form very fine and delicate, thread-like strucuture called root hairs. These root hairs absorb water and minerals from the soil.

In Bougainvillea, thorns are the modifications of stem. They are stiff, sharp structures, which have lost their growing point and become hard. They reduce transpiration as well as browsing by animals.

Perigynous flowers are found in rose.

Flowers can be categorised based on the position of the ovary in relation to the other parts of the flowers. When the floral plants arise from a position below the ovary, the flower is said to be hypogynous (hypo=below; gynous=flower) and the ovary is superior, e.g. China rose.

When the floral parts arise from a position above the ovary , the flower is epigynous (epi=above) and ovary is inferior, e.g. cucumbar and guava.

There is another special case of an inferior ovary where the bottom of sepals, petals and stamens are fused into a cup around the ovary called hypanthium (floral cup). Such, flower is termed as perigynous (peri = around), e.g. rose.

Lemon (Citrus sp.) belongs to family-Rutaceae, contains axile placentation.

Argemone belongs to family-Papaveraceae, contains parietal placentation. Dianthus belongs to family-Caryophyllaceae, contains free-central placentation. Marigold belongs to family-Asteraceae, contains: basal placentation.

Syconus fruit develops from hypanthodium inflorescence, eg Ficus carica, F. religiosa, F. benghalensis. The flask shaped receptacle encloses female flowers that gives rise to achene-like fruitlets. This fruit possesses a small pore protected by scaly leaves. The receptacle that becomes fleshy is edible.

The seeds of castor (Ricinus communis, family -Euphorbiaceae) are endospermic dicot seeds. They possess, endosperm which acts as the food storage tissue of seed. They also possess perisperm and cruncle.

Lady's finger or Okra or Abelmoschus esculentus belongs to the family malvaceae. The plant is native of tropical Africa. The fruits are light green, mucilaginous and contain numerous green or brown seeds.