1. Around 1900 the first dams were built on the Muskegon river, and this immediately cause a problem in the ecosystem by being a blockade for the movement of the water species, as well as causing higher mortality by killing them in the turbines.
2. By 1950 more dams were built, and the there were even more blockades on the way of the water species, so their movement was restricted even more, the mortality rates skyrocketed because of the disposing of the oxygen, temperature change, river flows changing etc.
3. Even though the scientists miss information from the period before the dams were built, since the information have started to be gathered it has been very obvious that the main factor for ruining the ecosystems on the Muskegon river are the dams by causing all sorts of changes in the water.
Electromagntic wave, such as an X-ray.
Explanation:
- Electromagnetic wave does not require any medium to travel. These waves propagate outwards from the source.
- They can travel even through the vacuum of outer space.
- The major source is the sun which emits radiation in the form of the Electromagnetic spectrum.
- These waves travel through oscillating electrical and magnetic fields generated by the oscillating charged particles.
- These waves oscillate in the perpendicular direction of planes concerning each other and are in form.
- Electromagnetic waves travel at speed of light.
River valley trade made them key economic areas.
Hope this helped. :)
Answer:
Lobster
Explanation:
Lobster was also known as the poor man's meal because the overabundance of these guys made it easy for people with no money to get their protein. In fact, these crustaceans were fed to prisoners, apprentices and slaves.
Answer:
Fields should be bigger to feed more people, but they are smaller because people live on those lands.
Explanation:
A higher population density means that there are more people in an area. As there are more people, there is not enough space for all of them to live in the city, so new cities and towns emerge occupying the field's lands used for cattle raising and agriculture. There should be larger fields to feed all the population, but they become smaller because parts of them are now populated.
