Answer is A. A population becomes separated by environmental factors into two groups that do not reproduce with one another.
When a population of a species become geographically separated then gene flow between them stops. Over a period of time, the population may become genetically different in response to the natural selection due to different environments. Selection and genetic drift will act differently on these two separated populations. This will results into two separate species. This type of speciation is called allopatric speciation.
Answer:
Methane is a chemical compound with the chemical formula CH4, symbolizing one atom of carbon and four atoms of hydrogen. It is a group 14 hydride and the simplest alkaline, and is the main constituent of natural gas. The relative abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it poses technical challenges due to its gaseous state under normal conditions for temperature and pressure. Methane naturally occurs both below ground and under the seafloor, and is formed by both geological and biological processes. In nature, methane is produced by the anaerobic bacterial decomposition of vegetable matter under water. Methane is important because it can be captured from landfills, can be burned to produce electricity, heat buildings, or power garbage trucks. Methane can also be captured from farm digesters, which are big tanks that contain manure and other waste from barns that house livestock such as cows and pigs. In fact, Jordan Dairy Farms in Massachusetts uses a biodigester to turn cow manure into methane gas, which is used for fuel or turned into electricity.
Answer:
4 Charles Darwin was not able to explain the variation
Most likely clay, silt and sand are to be found in samples of rocks.
A.
Commuters drive personal vehicles to their places of work: offices, manufacturing plants etc.
Some may use car pooling or mass transit like buses. But too many want the luxury and convenience of coming and going on their own terms.
IMHO car pooling and mass transit needs to be used more to reduce environmental harm.
