All questions of July Week 2 for NEET Exam

• Monocotyledonous roots
  Monocot roots do not undergo secondary growth because they lack vascular cambium, which is found in the vascular bundle between the xylem and phloem. 
• Monocotyledonous stems
  Monocot stems do not undergo secondary growth, but they can increase in girth. This is called anomalous thickening and does not result in the development of secondary xylem and phloem

The odd one out among the given options is option 'C', which represents the Electrostatic force.

**Viscous Force:**
- Viscous force refers to the resistance that a fluid (liquid or gas) exerts on an object moving through it.
- It is a type of frictional force that opposes the relative motion of the object and the fluid.
- Viscous force is responsible for phenomena like drag experienced by objects moving through a fluid medium.
- Examples of viscous force include the resistance experienced by a car moving through air or a boat moving through water.

**Frictional Force:**
- Frictional force is the force that opposes the motion or attempted motion of an object past another object with which it is in contact.
- It arises due to the roughness or irregularities present on the surfaces in contact.
- Frictional force plays a crucial role in our daily lives, such as walking, driving a car, or holding objects.
- It can be both advantageous (e.g., walking) and disadvantageous (e.g., wearing out of machine parts).

**Electrostatic Force:**
- Electrostatic force is the force of attraction or repulsion between charged objects.
- It arises due to the electric charge carried by the objects.
- Objects with the same charges repel each other, while objects with opposite charges attract each other.
- Electrostatic force is responsible for various phenomena such as the attraction of clothes after being dried in a dryer or the repulsion of two magnets.

**Air-Resistance:**
- Air resistance, also known as drag, is a force that opposes the motion of an object through the air.
- It is caused by the collision of air molecules with the object in motion.
- Air resistance depends on factors such as the shape and size of the object, the speed of motion, and the density of the air.
- It affects objects moving through the air, like a falling parachute or a moving car.

**Explanation:**
The odd one out is electrostatic force because it is the only option that does not involve the interaction between objects in motion or with a fluid medium. Electrostatic force is related to the interaction between charged objects, whereas the other three forces (viscous force, frictional force, and air resistance) are associated with the motion of objects through a medium (fluid or air).

Gravitational and electrical forces are conservative. Friction is non-conservative because the amount of work done by friction depends on the path. One can associate a potential energy with a conservative force but not with a non-conservative force.

Understanding the Stele
The stele is a crucial part of the plant root and stem anatomy, involved primarily in the transport of water, nutrients, and food. It is essential to differentiate which structures constitute the stele.
Components of the Stele
The stele primarily includes:
- Vascular Bundles: These are responsible for the conduction of water (xylem) and nutrients (phloem).
- Pericycle: This is the layer of cells just inside the endodermis, from which lateral roots arise.
- Endodermis: This is the innermost layer of the cortex, forming a selective barrier to regulate the flow of water and nutrients into the vascular system.
Other Structures
The following do NOT constitute the stele:
- Pith: This is central tissue found in some stems, but is not part of the stele.
- Cortex: This is the layer of ground tissue between the epidermis and the vascular tissues, also not included in the stele.
- Epidermis: This is the outer protective layer of the plant, which does not form part of the stele.
Conclusion
Thus, the correct answer is option 'B', as only three structures (vascular bundles, pericycle, and endodermis) comprise the stele. Recognizing these components is essential for understanding plant physiology, particularly in the context of nutrient and water transport.

Understanding Plant Tissues
Plant tissues are essential components of plants, classified into two main types: meristematic and permanent. Each type plays a vital role in the overall functioning of the plant.
Assertion (A) Explained
- Meristematic Tissues: These are undifferentiated cells that can divide and contribute to growth. They are found in regions of the plant that are actively growing, like tips of roots and stems.
- Permanent Tissues: These tissues are differentiated and have specific functions. They include parenchyma, collenchyma, and sclerenchyma, each serving unique roles.
Reason (R) Explained
- Functions of Plant Tissues: The main functions of plant tissues encompass:
- Food Assimilation: Tissues like parenchyma are involved in photosynthesis and nutrient storage.
- Storage: Specialized tissues store starch, oils, and water.
- Mechanical Support: Sclerenchyma and collenchyma provide structural integrity and support to the plant.
Linking Assertion and Reason
- The reason elaborates on the functions of plant tissues, which directly relate to the types of tissues mentioned in the assertion.
- Meristematic tissues contribute to growth, while permanent tissues fulfill specific roles such as support and storage, thereby justifying the assertion.
Conclusion
Thus, both the assertion and reason are true, and the reason correctly explains the assertion. Therefore, the correct answer is option 'A'. Understanding this relationship helps in grasping the fundamental concepts of plant biology, crucial for NEET preparation.

**Conservative Forces and Work Done over a Closed Loop**

In physics, a conservative force is a type of force that depends only on the initial and final positions of an object, and not on the path taken by the object. This means that the work done by a conservative force over any closed loop is zero.

**Explanation:**

To understand why the work done over a closed loop by a conservative force is zero, let's consider the definition of work done. Work is defined as the product of the force applied to an object and the displacement of the object in the direction of the force.

If a force is conservative, it can be expressed as the negative gradient of a scalar potential function. This means that the force can be written as the negative derivative of a potential energy function with respect to position.

Now, let's consider a closed loop. Since the starting and ending positions are the same, the change in potential energy over the loop is zero, as the potential energy depends only on the position. This implies that the change in potential energy is equal to the negative of the work done by the conservative force over the loop.

Since the change in potential energy is zero, the work done by the conservative force over the closed loop must also be zero. This means that the net work done by the conservative force in completing a closed loop is zero, regardless of the path taken.

**Example:**

For example, consider a ball moving in a gravitational field. The gravitational force is conservative, as it depends only on the position of the ball. If the ball is lifted to a certain height and then allowed to fall back to the starting position, the work done by the gravitational force over the closed loop is zero. This is because the potential energy at the starting and ending positions is the same, regardless of the path taken by the ball.

**Conclusion:**

In conclusion, for conservative forces, the work done over a closed loop is zero. This is because conservative forces can be expressed as the negative gradient of a potential energy function, and the potential energy depends only on the position of the object. Therefore, the change in potential energy over a closed loop is zero, resulting in zero work done by the conservative force.