Why do elephants have big ears?
To fly.
Not at all.
Ears basically help to hear.
Besides this, big ears of an elephant also help it to regulate its body temperature.
But how can ears help to regulate body temperature?
In living beings like elephants, blood supplies heat to all parts of the body.
Thus helping it to maintain the body temperature.
However, due to metabolic activities or hot climate, sometimes heat in the blood can increase.
Thus increasing the body temperature of the elephant.
Now, an elephant's big ears are filled with blood vessels which are very close to the surface of the skin.
Hence, when blood having more amount of heat flows through the ears of the elephant.
The heat from the blood escapes into the atmosphere cooling the blood and in turn cooling the elephant.
Why don't spiders stick to their webs?
I don't know.
Usually, a spider's web is made up of silk threads which are covered with droplets of glue.
This glue makes the threads sticky.
Now, when an insect flies through the web, the insect normally gets stuck to the sticky threads.
But, a spider does not get stuck because its legs have tiny hair like structures called setae.
When a spider walks on a sticky thread, the setae gets stuck onto the thread.
Helping the spider to get grip and support to walk.
Now as the point of contact is very less, the glue has very less surface area to stick.
Hence, the spider easily pulls its legs without sticking.
Besides this, a research suggests that certain spider's legs are covered with a special chemical coating.
This coating also helps the legs from sticking to the glue.
What is a tardigrade?
I don't know.
A tardigrade is one of the smallest animals.
It can grow only about 1 millimeter or less in length.
However, it is the toughest animal in the whole world.
It cannot be tougher than me.
All right.
Now listen.
Scientists say that tardigrades can survive in extremely inhospitable environments.
But how?
When the environment is inhospitable, the tardigrades enter a state called cryptobiosis.
In cryptobiosis, they curl up into a ball like structure called tun.
All their metabolic processes almost stop.
In this state, tardigrades can survive in about minus 459 degrees Fahrenheit.
Even in about 300 degrees Fahrenheit.
They can live deep in the oceans and withstand the huge pressure of water.
They can even survive in the vacuum of space and can withstand radiation.
Later, when the conditions are stable, they again come back to their normal form.
What is a stroke?
It is a new style of haircut.
No.
Through a complex system of arteries.
Our brain gets a continuous supply of oxygen and nutrients with the help of blood.
The cells of our brain alone use more than 20% of oxygen in our blood.
Hence, if the blood doesn't reach the brain cells, they can begin to die, thus giving us a stroke.
The most common stroke is Ischemic stroke.
Ischemic strokes occur when the arteries supplying blood to the brain get blocked.
Like the roads get blocked in a traffic jam, right?
Indeed.
Due to bad lifestyle choices and stress, fats and cholesterol gradually start building up in the arteries.
Thus, narrow them.
If this build up ruptures, a clot may form blocking the complete artery.
As a result, the brain cells begin to die due to lack of oxygen and nutrients.
Thus, giving us an Ischemic stroke.
What is an allergy?
It is a magic spell.
No.
Allergy is an overreaction of our immune system to usually harmless substances.
Like peanuts, milk, pollen, etc.
These substances are called allergens.
Our immune system has white blood cells or lymphocytes which protect us from foreign invaders.
Such as bacteria, viruses, parasites, etc.
These invaders are called antigens.
When a lymphocyte detects an antigen, it produces antibodies.
Antibodies destroy antigens and thus, protect us.
Now, if an allergen such as pollen is inhaled by an allergic person.
The lymphocytes of the allergic person for unknown reasons think that the allergen is an antigen.
Hence, lymphocytes overreact and produce antibodies which start attacking the allergen.
Besides this, as a protective response.
Some immune cells also trigger production of excess mucus resulting in running nose.
They even give rise to itching throat and watery eyes, thus causing an allergy.