// For construction new question objects
function question(answer, support, question, a, b, c, d) {
	this.answer = answer;
    this.support = support;
	this.question = question;
	this.a = a;
	this.b = b; 
	this.c = c;
	this.d = d;
	return this;
	}

// The array of questions, answers, options, and explanations
var units = new Array(
	new question("c", "A catastrophe or sudden act of great destruction and loss is a DISASTER.", "A catastrophe or sudden act of great destruction and loss is  _____.", "an achievement", "an accomplishment", "a disaster", "a warning"),
	new question("a", "To terrorize or intimidate someone is to THREATEN", "To terrorize or intimidate someone is to _____.", "threaten", "avert", "postpone", "preserve"),
	new question("d", "To avoid or prevent from happening is to AVERT.", "To avoid or prevent from happening is to _____.", "contaminate", "survive", "replace", "avert"),
	new question("a", "The study of the natural connections among plants, animals, people, and the environment is ECOLOGY.", "The study of the natural connections among plants, animals, people, and the environment is _____", "ecology", "economy", "geography", "environment"),
	new question("b", "Raw materials found in nature, such as minerals, trees, fresh water, and oil, that are useful to humans are NATURAL RESOURCES.", "Raw materials found in nature, such as minerals, trees, fresh water, and oil, that are useful to humans are _____.", "litter", "natural resources", "hazardous material", "refuse"),
	new question("b", "A slow increase in the temperature of the air around the earth is called global warming or THE GREENHOUSE EFFECT.", "A slow increase in the temperature of the air around the earth is called global warming or _____.", "the ozone layer", "the greenhouse effect", "an oil spill", "geothermal energy"),
	new question("a", "A covering of a poisonous gas found in parts of the earth's upper atmosphere is called THE OZONE LAYER.", "A covering of a poisonous gas found in parts of the earth's upper atmosphere is called _____.", "the ozone layer", "pesticide poisoning", "polar ice cap", "hazardous cargo"),
	new question("d", "A large mass of ice that moves slowly down a mountain is a GLACIER", "A large mass of ice that moves slowly down a mountain is _____", "a cascade", "a polar ice cap", "an iceberg", "a glacier"),
	new question("c", "A large piece of frozen ice in the sea is an ICEBERG.", "A large piece of frozen ice in the sea is  _____.", "an avalanche", "geothermal energy", "an iceberg", "a glacier"),
	new question("a", "To change from a solid to a liquid state is to MELT.", "To change from a solid to a liquid state is to _____.", "melt", "steam", "drip", "spill"),
	new question("d", "A dark, thick, oily liquid usually found between layers of rock in the earth and used to make fuels for heating, light, or engines is PETROLEUM.", "A dark, thick, oily liquid usually found between layers of rock in the earth and used to make fuels for heating, light, or engines is _____.", "steam", "natural gas", "coal", "petroleum"),
	new question("a", "A mineral made of dark brown or black carbon that is dug from the ground and burned for heat is COAL.", "A mineral made of dark brown or black carbon that is dug from the ground and burned for heat is _____.", "coal", "oil", "radiation", "sewage"),
	new question("c", "The business and process of taking minerals out of the earth is MINING.", "The business and process of taking minerals out of the earth is _____.", "oil spill", "melting", "mining", "natural gas"),
	new question("d", "An air-like substance used for cooking and heating that is piped out of the earth is NATURAL GAS.", "An air-like substance used for cooking and heating that is piped out of the earth is _____.", "petroleum", "coal", "solar energy", "natural gas"),
	new question("b", "Power that is related to heat found deep inside the earth is GEOTHERMAL ENERGY.", "Power that is related to heat found deep inside the earth is _____.", "nuclear energy", "geothermal energy", "hydroelectric energy", "solar energy"),
	new question("a", "A gas in the air made by heated water under pressure is STEAM.", "A gas in the air made by heated water under pressure is _____.", "steam", "natural gas", "radiation", "glacier"),
	new question("c", "Power that is related to the sun is SOLAR ENERGY.", "Power that is related to the sun is _____.", "nuclear energy", "geothermal energy", "solar energy", "hydroelectric energy"),
	new question("a", "Harmful or poisonous man-made substances are TOXIC CHEMICALS.", "Harmful or poisonous man-made substances are _____.", "toxic chemicals", "the ozone layer", "natural resources", "deforestation"),
	new question("b", "Dangerous garbage is HAZARDOUS WASTE.", "Dangerous garbage is _____.", "steam", "hazardous waste", "smog", "hazardous cargo"),
	new question("d", "A dangerous load or shipment carried by something is HAZARDOUS CARGO.", "A dangerous load or shipment carried by something is _____.", "coal", "hazardous waste", "litter", "hazardous cargo"),
	new question("a", "Pieces of trash on the ground are LITTER.", "Pieces of trash on the ground are  _____.", "litter", "toxic chemicals", "sewage", "natural resources"),
	new question("c", "Waste and liquid that goes from toilets to pipes underground are SEWAGE.", "Waste and liquid that goes from toilets to pipes underground are _____.", "radiation leak", "refuse", "sewage", "litter"),
	new question("a", "Air pollution from smoke or exhaust is SMOG.", "Air pollution from smoke or exhaust is  _____.", "smog", "fog", "steam", "natural gas"),
	new question("d", "The smoke or steam that escapes from a car's engine is automobile EXHAUST.", "The smoke or steam that escapes from a car's engine is automobile  _____.", "energy", "fog", "refuse", "exhaust"),
	new question("b", "A harmful condition produced by insect-killing chemicals is PESTICIDE POISONING.", "A harmful condition produced by insect-killing chemicals is  _____.", "oil spill", "pesticide poisoning", "radiation leak", "deforestation"),
	new question("b", "A removal of many trees by cutting or fire is 	DEFORESTATION.", "A removal of many trees by cutting or fire is  _____.", "exhaust", "deforestation", "contamination", "explosion"),
	new question("c", "To make unclean or unfit for use or consumption is to CONTAMINATE.", "To make unclean or unfit for use or consumption is to  _____.", "avert", "threaten", "contaminate", "litter"),
	new question("d", "To blow apart with force or to burst is to EXPLODE.", "To blow apart with force or to burst is to  _____.", "avert", "contaminate", "pollute", "explode"),
new question("d", "A painful experience or struggle is an ORDEAL.", " A painful experience or struggle is _____.", "a prediction", "a warning", "a threat", "an ordeal"),
new question("a", "A bad result or consequence of something is an AFTERMATH.", "A bad result or consequence of something is  _____.", "an aftermath", "a survivor", "contamination", "a survivor"),
new question("c", "A sudden violent movement of the earth's surface is an EARTHQUAKE.", "A sudden violent movement of the earth's surface is  _____.", "a tornado", "a hurricane", "an earthquake", "a seismograph"),
new question("b", "The point where different earth plates meet is a FAULT LINE.", "The point where different earth plates meet is  _____.", "a mudslide", "a fault line", "a glacier", "an avalanche"),
new question("d", "To make quick, repeated movments back and forth is to SHAKE.", "To make quick, repeated movments back and forth is to  _____.", "collapse", "escape", "recede", "shake"),
new question("b", "A machine that measures Earth's movements is a SEISMOGRAPH.", "A machine that measures Earth's movements is  _____.", "a torrent", "a seismograph", "an eruption", "an aftermath"),
new question("a", "To say what will happen in the future is to PREDICT.", "To say what will happen in the future is to _____.", "predict", "suffer", "affect", "recede"),
new question("b", "A falling of a dirt hillside after rain has turned it soft is a MUDSLIDE.", "A falling of a dirt hillside after rain has turned it soft is a  _____.", "a tsunami", "a mudslide", "a tidal wave", "a flood"),
new question("c", "A sudden breaking away of snow or rocks down a mountain is an AVALANCHE.", "A sudden breaking away of snow or rocks down a mountain is  _____.", "an aftermath", "a downpour", "an avalanche", "a torrent"),
new question("d", "To cover up or hide something in the ground is to BURY.", "To cover up or hide something in the ground is to  _____.", "dig", "avert", "recede", "bury"),
new question("a", "To move forcefully and quickly over or through something is to SWEEP.", "To move forcefully and quickly over or through something is to  _____.", "sweep", "warn", "threaten", "affect"),
new question("b", "To hurt or cause damage is to INJURE.", "To hurt or cause damage is to  _____.", "avert", "injure", "sweep", "affect"),
new question("c", "To get away from someone or something is to ESCAPE.", "To get away from someone or something is to  _____.", "postpone", "contaminate", "escape", "postpone"),
new question("d", "To lose strength and fall down or into ruin is to COLLAPSE.", "To lose strength and fall down or into ruin is to  _____.", "drown", "flood", "pollute", "collapse"),
new question("a", "To change, influence, or have an impact on is to AFFECT.", "To change, influence, or have an impact on is to  _____.", "affect", "suffer", "devastate", "warn"),
new question("b", "A sad event or disaster is a TRAGEDY.", "A sad event or disaster is a  _____.", "natural resource", "tragedy", "prediction", "warning"),
new question("c", "The number of people who die in an event is the DEATH TOLL.", "The number of people who die in an event is the  _____.", "seismograph", "fault line", "death toll", "survival rate"),
new question("d", "A person hurt or killed in a bad event is a victim or a CASUALTY.", "A person hurt or killed in a bad event is a victim or a  _____.", "rescuer", "threat", "survivor", "casualty"),
new question("a", "A person who lives through a life-threatening event is a SURVIVOR.", "A person who lives through a life-threatening event is a  _____.", "survivor", "threat", "savior", "minor"),
new question("b", "To experience pain or loss is to SUFFER.", "To experience pain or loss is to  _____.", "tremble", "suffer", "avert", "affect"),
new question("c", "Complete destruction or ruin is DEVASTATION.", "Complete destruction or ruin is  _____.", "escape", "contamination", "devastation", "threaten"),
new question("d", "Something that is very strong, serious, or dangerous is SEVERE.", "Something that is very strong, serious, or dangerous is  _____.", "minor", "deep", "shallow", "severe"),
new question("a", "MAJOR means main or most important.", " _____means main or most important.", "major", "minor", "shallow", "steep"),
new question("b", "A large and violent wind and rain storm a HURRICANE.", "  _____.", "flood", "hurricane", "tidal wave", "tsunami"),
new question("c", "Another word for a tidal wave is a TSUNAMI.", "Another word for a tidal wave is a  _____.", "tornado", "hurricane", "tsunami", "explosion"),
new question("d", "An adjective relating to a violent flood or downpour of water is TORRENTIAL.", "An adjective relating to a violent flood or downpour of water is  _____.", "dormant", "gust", "shallow", "torrential"),
new question("a", "A sudden heavy rain is a DOWNPOUR.", "A sudden heavy rain is  _____.", "a downpour", "a tornado", "a tsunami", "a gale"),
new question("b", "To move back is to RECEDE.", "To move back is to  _____.", "contaminate", "flood", "affect", "explode"),
new question("c", "A strong wind is a gust or a GALE.", "A strong wind is a gust or a  _____.", "downpour", "flood", "gale", "torrent"),
new question("d", "Hot, liquid volcanic rock is LAVA.", "Hot, liquid volcanic rock is  _____.", "ash", "gravel", "granite", "lava"),
new question("a", "The grayish, powdery substance left after something has burned is ASH.", "The grayish, powdery substance left after something has burned is  _____.", "ash", "gravel", "granite", "lava"),
new question("b", "A volcanic explosion is called an ERUPTION.", "A volcanic explosion is called  _____.", "a contamination", "an eruption", "a pollution", "a spill"),
new question("c", "A serious lack of food is a FAMINE.", "A serious lack of food is a  _____.", "torrent", "flood", "famine", "gust"),
new question("d", "To feel pain or die from lack of food is to STARVE.", "To feel pain or die from lack of food is to  _____.", "avert", "drown", "bury", "starve")

);