Ecology is the study of the relationships between living organisms, including humans and their physical environment. The German scientist Earnst Haeckel was the first to use this word in 1869.

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.

1. The first vitamin discovered in 1897 was thiamine, also known as vitamin B1.

2. Thiamine was discovered by Dutch physician Christiaan Eijkman.

3. Vitamin B1 helps body cells convert carbohydrates into energy and maintain proper functioning of the heart, muscles and digestive system.

1. Ichthyology is related to the study of fishes. It is a branch of zoology that studies the classification, morphology, physiology, behaviour, ecology, and evolution of fishes.

2. People working in the field of ichthyology are called ichthyologists.