Discussion topic
chemical energy sources are often portable and provide large amounts of energy. fossil fuels are one kind of chemical energy source. most of the energy we use in the united states is generated by the combustion of fossil fuels. however, fossil fuel combustion adds greenhouse gases to the atmosphere, mostly co2. one measure of the total amount of greenhouse gases that are emitted into the atmosphere each year is called a carbon footprint. read this article to compare the carbon footprint of an average person in the united states to an average person around the
world. knowing that greenhouse gases are
contributing to climate change, how can we
reduce our carbon footprint, particularly in the
united states? could hydrogen fuel replace
fossil fuels in the future? why or why not? should the size of a person's carbon footprint be limited by law? why or why not?

Two male mice, which we will call male a and male b, are both phenotypically normal. male a was from a litter that contained half phenotypically normal mice and half dwarf mice. the mother of male a was known to be homozygous for the normal igf2 allele. male b was from a litter of eight mice that were all phenotypically normal. the parents of male b were a phenotypically normal male and a dwarf female. male a and male b were put into a cage with two female mice that we will call female a and female b. female a is a dwarf and female b is phenotypically normal. the parents of these two females were unknown, although it was known that they were from the same litter. the mice were allowed to mate with each other, and the following data were obtained: female a gave birth to three dwarf babies and four normal babies. female b gave birth to four normal babies and two dwarf babies. which male(s)mated with female a and female b? male a with both females male a with female b, and male b with female a male a with female a, and male b with female b could not be determined male b with both females

Which of the following are the ingredients that go into the plant and are needed for photosynthesis? select all that apply. 1.) soil 2.) seeds 3.) carbon dioxide 4.) minerals 5.) glucose (sugar) 6.) water 7.) light energy (sunlight) 8.) oxygen 9.) air

With regard to enzymes, key is to lock as a) substrate is to activation energy eliminate b) product is to substrate. c) enzyme is to active site. d) substrate is to active site.