Photosynthesis is the major source of this gas in Earth's atmosphere.
What is O2 or oxygen?
100
This is the primary cause of high death rates in phase I or the pre-industrial stage.
What is infant or childhood mortality?
100
Depletion of fishing stocks in the North Atlantic, pollution of a local stream from runoff, and overgrazing of public land are examples of this.
What is tragedy of the commons?
100
Runoff from agricultural fields, highways, and parking lots is an example of this.
What is non-point pollution?
100
This is the reason there has been increased skin cancer rates in Australia.
What is ozone depletion?
200
This is an example of a marine keystone species that keeps sea urchins in check.
What is the sea otter?
200
As a country goes through the demographic transition, the greatest rate of population growth takes place during this phase.
What is the industrial phase?
200
Road construction, logging, and mining are banned in this federal land.
What are wilderness areas?
200
This colorless, odorless gas is natural and occurs as a product of decay from uranium.
What is radon?
200
This is a greenhouse gas that is also a by-product of anaerobic respiration in landfills, swamps, rice paddies, and animal guts.
What is methane (CH4)?
300
Approximate efficiency of the conversion of light energy to chemical energy in photosynthesis.
What is 1%?
300
In a human population undergoing the demographic transition, this rate generally decreases first.
What is death rate?
300
Put sand, clay, and silt in the correct order of soil particles from smallest to largest.
What is clay, silt, sand?
300
Increased amounts of this will result in accelerated eutrophication when introduced into streams, lakes, and bays.
What is nitrogen, phosphorous, or nutrients?
300
Protection of this is the best long term method of preventing extinctions.
What is habitat?
400
An energy transformation occurs and results in increased disorder.
What is entropy or the second law of thermodynamics?
400
These organisms have fewer young, slower population cycles, less likely to be invasives, have longer life spans, and reach sexual maturity later.
What are K-strategest species?
400
The process by which plant roots absorb ammonium ions and nitrate ions for use in making molecules such as DNA, amino acids, and proteins
What is assimilation?
400
This process of extracting and separating gold in remote regions often results in environmental contamination of this compound.
What is cyanide?
400
Many scientists maintain that a rise in sea level has occurred in the last hundred years as a result of global warming. This factor best explains such a rise.
What is thermal expansion of the ocean?
500
This is the zone of a pond or lake in which rooted, emergent plants such as cattails and rushes are located.
What is littoral?
500
In 2003, the current global human population was about 6.1 billion and was growing at an annual rate of 1.35 percent. If world population were to grow at this this rate for the following year, approximately how many people would be added?
What is 8 x 10^9?
500
Compared with with people in developing countries, people in industrialized countries are more likely to eat this food.
What is meat?
500
These are the three main anthropogenic sources of gaseous air pollutants in the US.
What is industry, transportation, and energy production?
500
This is the main substance that is released by CFC's and catalyzes a chain reaction that breaks down ozone in the upper atmosphere.