Explanation

Antonie van Leeuwenhoek is credited with the discovery of bacteria.

In 1676, using a primitive microscope, he observed and described microorganisms.

Including bacteria and protozoa, which he referred to as "animalcules".

Explanation

 Coal gas composition:

Typically contains around 50% hydrogen, 35% methane, and 10% carbon monoxide. 

Production method:

Coal is heated in the absence of air to produce these gases. 

Explanation

A marsupium, or pouch, is a specialized structure in marsupials (like kangaroos, koalas, and opossums)

where the young are carried and continue to develop after birth.

Rearing the young ones:

The pouch provides protection and warmth, ensuring the young can continue their development after birth.

Feeding the young ones:

The young have access to the mother's milk while in the pouch.

Explanation

Two Protective Layers:

Renal Capsule: The inner layer, a tough fibrous membrane directly covering the kidney.

Adipose Capsule: The outer layer, a fatty cushion that protects against physical shock.

Explanation

Hydrochloric acid (HCl): is a strong inorganic acid, also known as a mineral acid.

Citric acid, acetic acid, and lactic acid are organic acids found in citrus fruits, vinegar, and muscle tissue, respectively.

Explanation

 When a ball is thrown vertically upwards, its velocity decreases as it rises due to gravity.

At the maximum height, the velocity becomes zero before it starts to fall back down.

Explanation

A bee is a flying insect known for pollination and producing honey.

It belongs to the order Hymenoptera, which also includes wasps and ants.

Explanation

A thermos flask is used to maintain the temperature of liquids, keeping hot things hot and cold things cold for extended periods.

It achieves this by minimizing heat transfer through a combination of insulation and a vacuum. 

Explanation

Temperature: High during the day (often above 35°C or 95°F), cooler at night.

Rainfall: Very low, usually less than 250 mm (10 inches) per year.

Humidity: Low, making the air feel dry.

Examples: Sahara Desert (Africa), Arabian Desert (Middle East), parts of Arizona and Nevada (USA).

Vegetation is sparse, and plants/animals are adapted to conserve water.

Explanation

 Silicon constitutes approximately 27.7% of the Earth's crust by weight.

It is the second most abundant element in the crust, following oxygen.