All questions of May for NEET Exam

The scientific name of the most common species of frog found in India is Rana tigrina.
- Genus and species:
Rana tigrina is the scientific name for the Indian bullfrog. The genus name is Rana, which is a common genus name for frogs, and the species name is tigrina.
- Physical characteristics:
Indian bullfrogs are known for their large size, with males growing up to 15 cm in length. They have a distinct yellow throat and a brownish-green body with dark spots.
- Habitat:
These frogs are commonly found in freshwater habitats such as ponds, lakes, and wetlands across India. They are also known to inhabit agricultural fields and urban areas.
- Behavior:
Indian bullfrogs are known for their loud calls during the mating season, which is usually during the monsoon months. They are carnivorous and feed on a variety of insects, small vertebrates, and even other frogs.
- Conservation status:
While the Indian bullfrog is currently listed as a species of least concern on the IUCN Red List, they face threats from habitat loss, pollution, and overexploitation for food and traditional medicine.
Overall, Rana tigrina is an important species of frog in India, playing a crucial role in the ecosystem as both predator and prey.

Epidermis
The epidermis is the outermost protective layer of a typical young dicotyledonous stem. Let's delve into why the epidermis is the outermost protective layer.

Function of Epidermis:
- The epidermis acts as a protective barrier, preventing water loss, physical damage, and invasion by pathogens.
- It also helps in the exchange of gases and regulates the movement of water and minerals into and out of the stem.

Structure of Epidermis:
- The epidermis is made up of a single layer of closely packed cells.
- The outer walls of these cells are often covered by a waxy cuticle, which further helps in reducing water loss.

Specialized Cells in Epidermis:
- The epidermis may contain specialized cells such as stomata, which are responsible for gas exchange, and trichomes, which provide protection against herbivores and reduce water loss through transpiration.

Comparison with Other Tissue Layers:
- The cortex, endodermis, and pericycle are internal layers of the stem that provide structural support, storage, and transportation of water and nutrients.
- The epidermis, being the outermost layer, plays a crucial role in protecting these internal tissues.
In conclusion, the epidermis is the outermost protective layer of a typical young dicotyledonous stem, serving vital functions in protection, gas exchange, and regulation of water and mineral movement.

Understanding Dicot Roots
In dicotyledonous plants, the structure of the root is essential for their growth and nutrient transport. The arrangement of vascular tissues, specifically xylem and phloem, plays a significant role in these functions.
Xylem and Phloem Arrangement
In a typical dicot root:
- Xylem: Responsible for water and mineral transport from the soil to the rest of the plant.
- Phloem: Responsible for the transport of organic nutrients, especially sugars produced during photosynthesis.
Patches of Vascular Tissue
The arrangement of xylem and phloem in dicot roots is characterized by:
- Two patches: In the cross-section of a dicot root, you will usually find two distinct patches of xylem and phloem.
- Xylem Shape: The xylem is typically shaped like a star or a cross.
- Phloem Location: The phloem is located in between the arms of the xylem in these patches.
Significance of Two Patches
The presence of two patches of xylem and phloem in dicot roots is crucial for:
- Efficient Transport: This arrangement allows for efficient transportation of water and nutrients.
- Structural Support: The star-like shape of the xylem provides structural integrity to the root.
Conclusion
Thus, the correct answer to how many xylem and phloem patches are usually present in a dicot root is two (option B). This configuration ensures that dicots can effectively manage their water and nutrient requirements for growth and development.

The protective coloration in frogs that allows them to change color to hide from their enemies is called camouflage.

Monocotyledonous stems have vascular bundles that are "conjoint and closed." This means the vascular bundles are scattered throughout the stem and have closed bundles with no cambium present.

Vascular Bundle Arrangement in Monocot Stems
Monocots, or monocotyledons, are a group of flowering plants characterized by specific structural features, especially in their stems. One significant aspect is the arrangement of vascular bundles.
Scattered Vascular Bundles
- In monocot stems, the vascular bundles are arranged in a scattered pattern throughout the stem's cross-section.
- This arrangement contrasts with dicots, where vascular bundles are typically arranged in a ring formation.
Components of Vascular Bundles
- Each vascular bundle in monocots consists of both xylem and phloem tissues.
- The xylem is usually located towards the inside (center) of the stem, while the phloem is situated on the outside.
Significance of Scattered Arrangement
- The scattered arrangement allows monocots to grow tall and maintain structural integrity, which is vital for plants like grasses and palms that experience wind and other environmental factors.
- It also enhances the plant's ability to transport water and nutrients efficiently across the stem.
Examples of Monocot Plants
- Common examples of monocots include grasses, lilies, and palms, all of which exhibit this distinct vascular arrangement.
In summary, the scattered arrangement of vascular bundles in monocot stems is a defining characteristic that supports their growth and adaptability in various environments. This structural feature plays a crucial role in the overall functioning and survival of these plants.

In a dicot stem, the characteristic arrangement of vascular bundles is "conjoint, open," meaning they are arranged in a ring-like pattern and have endarch protoxylem.

The ventricle of the frog's heart is responsible for pumping oxygenated blood to all parts of the body through the arterial system. It is an essential part of the circulatory system.

Uriniferous tubules or nephrons in frogs are responsible for filtering and processing waste products from the blood, ultimately leading to the formation of urine as part of the excretory system.