Glossary

Term	Definition
Humoral Immunity	Humoral immunity is an antibody-mediated adaptive immune response targeting extracellular pathogens (bacteria, toxins) in bodily fluids ("humors"). It involves B-cell maturation into plasma cells that secrete antibodies (immunoglobulins) to neutralize or eliminate antigens, often activating the complement system, contrasting with cell-mediated immunity. Vaccines
Hydrocarbons	Substances containing only hydrogen and carbon. Fossil fuels are made up of hydrocarbons. Climate Change Denial
Hydrologic Cycle	The process of evaporation, vertical and horizontal transport of vapor, condensation, precipitation, and the flow of water from continents to oceans. It is a major factor in determining climate through its influence on surface vegetation, the clouds, snow and ice, and soil moisture. Climate Change Denial
Hydrosphere	The component of the climate system comprising liquid surface and subterranean water, such as: oceans, seas, rivers, fresh water lakes, underground water etc. Climate Change Denial
Hypothesis	A testable, falsifiable prediction or explanation about a relationship between two or more variables. Science
Identity-protective cognition	Dan Kahan's term for the tendency to process information in ways that protect one's social identity and group affiliations, even at the cost of accuracy. Antiscience
Ideological / Political Bias	When political agendas override evidence, leading to the rejection of scientific findings that conflict with personal or group beliefs. Science General
Illusory Truth Effect	A cognitive bias where people are more likely to believe a statement is true simply because they have been exposed to it repeatedly. Our brains confuse the ease of processing familiar information with actual truth, making repeated falsehoods feel plausible. Antiscience
Immune System	The complex system in the body responsible for fighting disease. Its primary function is to identify foreign substances in the body (bacteria, viruses, fungi, or parasites) and develop a defense against them. This defense is known as the immune response. It involves production of protein molecules called antibodies to eliminate foreign organisms from the body. Vaccines
Immunity	Protection against a disease. There are two types of immunity, passive and active. Immunity is indicated by the presence of antibodies or other components in the blood and can usually be determined with a laboratory test. See active and passive immunity. Vaccines