Low pressure – when reading of the barometer is lower than inHg, this is considered as low air pressure, which is associated with warm air and rainstorm. So, clearly, a falling barometer indicates bad weather is ahead.

The average salinity of sea water is 3.5% or 35 parts per thousand. In other words, for every 1 litre of sea water there is 35 grams of dissolved salts (NaCl) .

A flexible tube called an endoscope is used to view different parts of the digestive tract. When passed through the mouth (as shown on the left), an endoscope can be used to examine the esophagus, stomach, and some of the small intestine.

Acetylene is the only fuel gas suitable for gas welding because of its favourable flame characteristics of both high temperature and high propagation rates. Other fuel gases, such as propane, propylene or natural gas, produce insufficient heat input for welding but are used for cutting, torch brazing and soldering.

Bile juice is produced by the liver and stored in the gallbladder, which is a small organ located beneath the liver. When needed, bile is released from the gallbladder into the small intestine to aid in the digestion and absorption of fats and fat-soluble vitamins. So, the correct answer is the liver secretes bile juice, and it is stored in the gallbladder before being released into the small intestine.

Vitamins A, D, E, and K are called the fat-soluble vitamins, because they are soluble in organic solvents and are absorbed and transported in a manner similar to that of fats. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E, can cause nerve problems.

This is a fundamental constant in chemistry that represents the number of atoms or molecules in one mole of a substance. (Option 4 is correct) Its value is approximately 6.022 x 10²³, and it is denoted by the symbol "N_A". Avogadro's number is a key concept in stoichiometry. The branch of chemistry deals with the quantitative relationships between reactants and products in chemical reactions.