Explanation

The medulla oblongata is located in the brainstem.

It regulates involuntary functions such as heartbeat, breathing, and blood pressure.

The cardiac center within the medulla controls heart rate and force of contraction.

It receives signals from the autonomic nervous system (sympathetic and parasympathetic).

Explanation

The troposphere is the lowest layer of Earth’s atmosphere.

It extends from the Earth’s surface up to about 8–15 km (varies with latitude).

All weather phenomena like rain, clouds, and storms occur in this layer.

It contains approximately 75–80% of the atmosphere’s mass.

The temperature in the troposphere decreases with altitude.

Explanation

Magma is molten rock beneath the Earth’s surface.

When it erupts through a volcano or reaches the surface, it is called lava.

Lava cools and solidifies to form igneous rocks.

The flow of lava can create volcanic landforms like lava plateaus and volcanic cones.

Lava temperature ranges from 700°C to 1,200°C, depending on its composition.

Explanation

Metamorphic rocks are formed from pre-existing rocks (igneous, sedimentary, or older metamorphic rocks).

They are changed by high heat and/or pressure without melting.

Common examples include marble (from limestone) and gneiss (from granite).

The process is called metamorphism, meaning “change in form.”

Explanation

Explanation

O negative (O⁻) blood group is called the universal donor.

It can be transfused to any blood group (A, B, AB, or O).

O⁻ lacks A, B, and Rh antigens, preventing immune reactions in recipients.

Explanation

Blood circulation rate in human arteries varies, fastest in the aorta (around 30-40 cm/s) 

In capillaries, the speed drops significantly to allow nutrient and gas exchange.

Blood velocity is highest in arteries, moderate in veins, and slowest in capillaries.

Proper circulation speed ensures efficient delivery of oxygen and nutrients throughout the body.

Explanation

Chromosomes are thread-like structures found in the nucleus of a cell.

They carry genetic information in the form of DNA.

Humans have 46 chromosomes (23 pairs) in each cell.

Chromosomes determine hereditary traits passed from parents to offspring.

They play a key role in cell division, growth, and reproduction.

Explanation

Bile is produced by the liver but stored in the gall bladder.

The gallbladder releases bile into the small intestine when fatty foods are present.

Bile helps in the digestion and absorption of fats.

It also neutralizes stomach acid entering the small intestine.

Gall bladder function is crucial for efficient fat metabolism in the body

Explanation

Metalloids have properties of both metals and non-metals.

They can conduct electricity better than non-metals but worse than metals.

Examples include silicon, boron, and germanium.

Metalloids are widely used in semiconductors and electronics.

Their mixed properties make them important in modern technology.