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Endocrine organs release their products (usually hormones) directly into the blood. The pancreas contains islets of Langerhans which are made up of alpha and beta cells. Beta cells secrete insulin and alp...

. increase in the number of cases of antibiotic resistance . increase in risk of horizontal gene transfer of resistance . resistant bacteria causes harm/ ineffective medical treatments . reduces risk of/ ...

Vaccines are made of dead or inactive pathogens. White blood cells in the body come into contact with the pathogen and produce antibodies which destroy the pathogen. The body produces memory cells which m...

Natural selection describes the selective pressure favouring those species with certain phenotypes (characteristics) which make them better suited to the environment than other species. Those with favoura...

Genetic information is stored in the nucleus as DNA. Humans have 46 molecules of DNA in each cell; each molecule known as a chromosome. When the cell is in interphase of the cell cycle, the DNA is in the ...