Each of the following are true statements about changes that occurred between 1800 and 1950 AD. Select one or more that could account for the direction of change in the population growth rate you calculated in the previous question. Select all that apply: Select one or more: a. Advances in mechanized farming and pest control resulted in rising crop yields per acre (more food grown per farmed acre). b. Air and water pollution that started with large-scale combustion of fossil fuel such as coal since the industrial revolution, and prior to implementation of environmental legislation as of the 1960s resulted in a rising number of associated chronic diseases such as cancer, pulmonary, and cardiovascular diseases. c. The number of children born to each mother declined from 6-10 in 1800 to 2-4 by 1950. d. Advances in medicine led to a dramatic reduction in mortality, particularly infant mortality. e. Changes in weapons technology led to dramatically higher casualty-rates also of civilians during wars, starting with the First World War. f. Technological advances, particularly in irrigation technology and industrial production of fertilizers, allowed for expansion of agriculture onto land that was previously unsuitable for growing of crops.