Explanation

The formula for calculating the density of an ideal gas is d = PM/RT, where: 

• d: is the density of the gas
• P: is the pressure of the gas
• M: is the molar mass of the gas
• R: is the ideal gas constant
• T: is the temperature of the gas in Kelvin

The ideal gas law is expressed as PV = nRT, where 'n' is the number of moles.

Density (d) is mass (m) divided by volume (V), so d = m/V.

We can relate the number of moles (n) to mass (m) and molar mass (M) using n = m/M.

Substituting this into the ideal gas law, we get PV = (m/M)RT.

Rearranging the equation to solve for density (d = m/V), we get d = PM/RT. 

Explanation

He had his breakfast at 9 o’clock.

The sentence refers to a specific time in the past ("at 9 o’clock"), so the correct tense is simple past.

"Had" is the simple past tense of "have," and it fits well with a completed past action at a specific time.

Explanation

The breakdown of alveoli in the lungs is called Emphysema. 

Emphysema is a lung condition where the small air sacs (alveoli) are damaged, causing them to break down and merge into larger spaces, reducing the surface area available for gas exchange. 

Explanation

The enzyme that converts sucrose into glucose and fructose is called invertase

It is also known as sucrase or beta-fructofuranosidase.

This process is known as hydrolysis, where water is used to break the glycosidic bond between glucose and fructose in sucrose.

Explanation

 "Took" is the correct past tense of the verb "take," which is appropriate for the sentence.

Explanation

A protostome is an animal where the first opening that forms during embryonic development (the blastopore) becomes the mouth.

While the second opening develops into the anus. 

Explanation

Calcium chloride (CaCl₂) is a hygroscopic substance, meaning it absorbs moisture from the air.

It is commonly used as a drying agent in desiccators to keep the environment moisture-free.

Explanation

 Lodicules are small, scaly structures found at the base of a grass flower.

They are essentially modified parts of the perianth, which is the non-reproductive part of a flower.

The perianth consists of sepals and petals (or tepals if they are undifferentiated).

In grasses, the perianth is reduced and modified into these small scales called lodicules.

Explanation

Robert Koch established the germ theory of disease by demonstrating a causal relationship.

Between specific microorganisms and particular diseases, most notably with his research on anthrax.

Explanation

The intestinal parasite that causes amoebic dysentery in humans is Entamoeba histolytica.

Amoebic dysentery is a disease caused by the protozoan parasite Entamoeba histolytica.