Ankyloglossia is a condition in which the tongue is almost c…

Ankyloglossia is a condition in which the tongue is almost completely anchored to the floor of the mouth along its midline. This causes the person to have extreme difficulty talking and manipulating food during the process of mastication. The abnormal overgrowth of what structure would cause this condition?

Researchers are studying the influence of coffee consumption…

Researchers are studying the influence of coffee consumption on heart disease and find that those who report drinking more coffee also report a higher incidence of heart disease. However, it may be the case that those who drink coffee are also more likely to smoke cigarettes and the cigarette smoking is having an influence on the relationship between caffeine consumption and heart disease. What is this an example of?