All questions of Control and Coordination for Class 10 Exam

Correct option is B as auxin , cytokinin and gibberellins are growth promoting plant hormones while Abscisic acid is the growth inhibitior plant hormone.

Understanding Insulin Production in the Pancreas
The pancreas plays a crucial role in maintaining blood sugar levels through the secretion of insulin. This hormone is essential for the regulation of glucose in the bloodstream.
When Blood Sugar Levels Rise
- Insulin Release: The pancreas increases insulin production when blood sugar levels rise, particularly after eating carbohydrates.
- Glucose Uptake: Insulin facilitates the uptake of glucose by cells, allowing them to use it for energy.
- Storage of Excess Glucose: Insulin also promotes the storage of excess glucose in the liver and muscles as glycogen, thereby lowering blood sugar levels.
Consequences of High Blood Sugar
- Hyperglycemia: Persistently high blood sugar can lead to conditions like diabetes. Insulin helps to prevent this by normalizing glucose levels.
- Feedback Mechanism: The body uses a feedback loop; when blood sugar rises, insulin is secreted, and when it falls, insulin production decreases.
Summary
In summary, the correct answer is that the pancreas increases insulin production when blood sugar levels rise. This process is vital for maintaining homeostasis and ensuring that our bodies function effectively. Understanding this mechanism is essential for recognizing how diet and lifestyle choices can impact overall health.

> Sensory neuron > Interneuron > Motor neuron > Effector

b) Sensory neuron > Motor neuron > Interneuron > Effector

c) Effector > Motor neuron > Interneuron > Sensory neuron

d) Receptors > Effector > Sensory neuron > Interneuron > Motor neuron

Understanding Gibberellin
Gibberellins are a group of plant hormones that play a crucial role in various growth processes. Their primary function is significantly related to stem growth.
Key Functions of Gibberellins:
- Stimulating Stem Elongation: Gibberellins promote cell elongation, particularly in stems, leading to increased height and overall growth of the plant. This process is essential for plants to reach light and optimize photosynthesis.
- Promoting Cell Division: While gibberellins do influence cell division, their primary role centers on elongation rather than dividing cells. This is why their effect is more pronounced in stems.
- Enhancing Germination: Gibberellins play a pivotal role in seed germination. They break dormancy and initiate the growth process by stimulating enzymes that mobilize stored food in seeds.
- Influencing Flowering: Some gibberellins can also affect flowering processes, particularly in certain plants that require specific conditions to bloom.
In Summary:
Gibberellins are primarily involved in:
- Promoting stem growth and elongation, allowing plants to achieve greater heights.
- Supporting other growth processes, but their most notable function is in enhancing stem development.
Thus, option 'D'—assisting stem growth—accurately describes the primary function of gibberellins in plants, distinguishing them from other growth hormones that may inhibit growth or focus on root development.

Involuntary Actions Controlled by the Medulla
The medulla oblongata is a crucial part of the hindbrain, responsible for regulating several vital involuntary actions essential for survival.
Regulation of Respiration
- The medulla plays a key role in controlling the rhythm and rate of breathing.
- It contains respiratory centers that send signals to the diaphragm and intercostal muscles, facilitating inhalation and exhalation.
- It responds to changes in carbon dioxide and oxygen levels in the blood, ensuring the body's respiratory needs are met.
Other Functions of the Medulla
- While respiration is a primary function, the medulla also regulates:
- Heart rate: It influences cardiac function by controlling the autonomic nervous system.
- Blood pressure: It helps in maintaining blood pressure through vasomotor control.
- Reflex actions: The medulla is involved in reflexes such as coughing, sneezing, and swallowing.
Why Other Options Are Incorrect
- Control of Posture and Balance: This function is primarily managed by the cerebellum, which coordinates muscle movements and maintains balance.
- Precision of Voluntary Actions: The motor cortex and basal ganglia are responsible for the precision and coordination of voluntary movements, not the medulla.
- Reflex Movements of Head, Neck, and Trunk: While the medulla does play a role in some reflex actions, it is not the primary center for all reflex movements of the head, neck, and trunk, which involve different neural pathways.
Conclusion
In summary, the medulla oblongata’s primary involuntary action is the regulation of respiration, making option 'A' the correct answer. Its role in maintaining vital functions is essential for life.