There are four stages to the classical demographic transition model. pre-transitional europe was characterized by high and fluctuating mortality and a high birth rate. the transition model began to progress into and through stage 2 in the late 18th and early 19th century. all but one contributed to the decline in mortality. a) enacting measures to provide clean water supplies. b) public health advances including quarantine of settlements undergoing epidemics. c) the development of vaccines to prevent disease and antibiotics to treat infection. d) widespread acceptance of germ theory resulting in more hygienic practices, including hand washing and sterilizing medical equipment and infants’ bottles.

      n

a researcher conducts an experiment on the secretion of a particular hormone in mice. scientists inject mice with a substance that stimulates the production of the hormone. the scientists then test the levels of hormones produced by the mice. the tool used to measure the hormones consistently detects the levels at 10 points lower than the actual hormone levels in the mice. this tool makes measurements, but the measurements aren't .

explanation:

no u

the rocks are classified by the geological process they are formed by. the three main groups of rocks are igneous, metamorphic, and sedimentary. minerals are not they are classified under the chemical classes they are in. these groups include silicates, sulfates and carbonates.

not always but somethings can be reproduced in a laboratory.