Gases such as carbon dioxide and methane that trap heat in the atmosphere. These gases are emitted from a variety of natural sources like forest fires, and human sources like the combustion of gasoline and natural gas.

The natural home of an animal or plant

The process in which natural habitat is rendered functionally unable to support the species present.

The natural homes or environments of an animal, plant, or other organism

The force needed to cause an extension/compression in a spring is directly proportional to its extension/compression.

Regulatory substances produced in organisms and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.

Electrical energy produced by moving water

Energy or power produced by moving water.

A proposal intended to explain certain facts or observations.

Ignaz Semmelweis was a Hungarian physician whose work demonstrated that hand-washing could drastically reduce the number of women dying after childbirth. Until the late 1800s surgeons did not scrub up before surgery or even wash their hands between patients, causing infections to be transferred from one patient to another. Through vigorous statistical analysis, Semmelweis figured out where the problem lay and introduced rigorous hand-washing rules in the maternity ward. Deaths were drastically reduced and Semmelweis became known as the ‘saviour of the mothers’.
 
REF :  http://www.sciencemuseum.org.uk/broughttolife/people/ignazsemmelweis.aspx

A procedure in which eggs (ova) from a woman's ovary are removed. They are fertilized with sperm in a laboratory procedure, and then the fertilized egg (embryo) is returned to the woman's uterus.

The independent variable is the variable for which values are changed or selected by the investigator.

The invasion and multiplication of microorganisms such as bacteria, viruses, and parasites that are not normally present within the body

Disorders caused by organisms — such as bacteria, viruses, fungi or parasites

Energy in the region of the electromagnetic radiation spectrum at wavelengths longer than those of visible light,but shorter than those of radio waves

Interference refers to the superposing of two or more coherent waves to produce regions of maxima and minima in space, according to the principle of superposition.

The quantity between readings, eg a set of 6 readings equally spaced over a distance of 50 cm would give an interval of 10 centimetres.

A unit of energy.

Key Stage 3 (KS3) is the legal term for the three years of schooling in maintained schools in England and Wales normally known as Year 7, Year 8 and Year 9, when pupils are aged between 11 and 14.

Key Stage 4 (KS4) is the legal term for the two years of school education which incorporate GCSEs, and other exams, in maintained schools in England, Wales and Northern Ireland—normally known as Year 10 and 11 in England and Wales, and Year 11 and Year 12 in Northern Ireland, when pupils are aged between 14 and 16.

A process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land

People  who buy land with the sole intention of selling it on for a profit.

A fungus in symbiotic union with an alga and having a greenish, gray, yellow, brown, or blackish colour

A hormone secreted by the anterior pituitary gland that stimulates ovulation in females and the synthesis of androgen in males

dull : without a shine

A microorganism, especially a bacterium causing disease or fermentation

An organism that can be seen only with the aid of a microscope and that typically consists of only a single cell.

The moment of a force about a point is the product of the force with the perpendicular distance of the force from that point.

A nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland