<span>Igneous or metamorphic. Depending on the energy of the river, they could be anything from large, rounded cobbles or pebbles (as per classification of the Udden-Wentworth Scale), or sand and gravel as identified under other systems. Or angular clasts that haven't been rounded by moving along the bed. Note that the Udden-Wentworth is usually applied to sedimentary features, but can also be used in classifying the *size* of any rock. </span>
Answer:
sympatric
Explanation:
Speciation is the process by which new species originate and there are several mechanisms and processes by which speciation can take place.
When speciation occurs in a common geographical area where there are no barriers preventing the mating of species and the members of the species lie in close proximity to one another however, even in such conditions new species arise because of some differential characteristics. Such a speciation is termed as sympatric speciation.
In the given situation, the individuals that undergo genetic doubling get reproductively isolated from the original population because of incompatibility to mate even though they have close proximity with each other.
Therefore, the new species of evening primrose have arisen due to sympatric speciation.
In physics, a contact force is a force that acts at the point of contact between two objects, in contrast to body forces. Contact forces are described by Newton's laws of motion, as with all other forces in dynamics. Contact force is the force in which an object comes in contact with another object.
Hope this helps!
