The correct answer is - D) covered by warm shallow seas.
The fact that the crinoids are have an abundance in the fossil records in Pennsylvania in the Mississippian Period, tells us that this area was covered with shallow and warm seas. The reason why we can get that conclusion is that the crinoids live only in that kind of environment, so it simply a logical conclusion.
The geological data is also confirming this, as it is easily noticeable in the layers that during this period of the geologic past, what is now Pennsylvania, was covered with shallow sea waters. Also, this waters were warm too, as the climate was warm and humid and that period, so it was a perfect environment for the crinoids to flourish.
Answer:
Explanation:
Types of Mutations. There are a variety of types of mutations. ...
Chromosomal Alterations. Chromosomal alterations are mutations that change chromosome structure. ...
Point Mutations. A point mutation is a change in a single nucleotide in DNA.
Answer:
difference:
1. The generation mechanism is different, the mechanical wave is generated by mechanical vibration; the electromagnetic wave generation mechanism is also different, there is the periodic movement of electrons (radio waves); the outer electrons with atoms are generated after being excited (infrared, visible, ultraviolet) The inner electrons with atoms are generated after excitation (roentgen rays); the nuclei with atoms are generated after excitation (gamma rays).
2. The propagation mechanism is different: the mechanical interaction between the particles and the alternating induction of the electromagnetic field.
3. Mechanical waves have both transverse waves and longitudinal waves; electromagnetic waves are material waves and belong to transverse waves.
4. The influence of the medium on the propagation speed is different
Explanation:
https://qiaodahai.com/similarities-and-differences-between-mechanical-waves-and-electromagnetic-waves.html
Answer:
Soil can become waterlogged. The water can cut off the air supply to the roots and to the organisms that live in the soil. If the roots do not receive enough oxygen, the plants will die because they rely on oxygen to complete photosynthesis.
Explanation:
Mature DNA cells do NOT contain DNA.
