Answer:
B. Aerobic bottom water
D. High organic productivity in the overlying oxygen rich water
Explanation:
A Shale is a sedimentary rock usually formed from silt and clay-size mineral. There are different colors of Shale. The Black Shale is formed under anaerobic conditions. This means that oxygen is deficient in the water where the Shale forms.
A little amount of organic materials is required for the formation of Black Shale and because Black Shale is formed in an environment lacking oxygen, an oxygen-rich water would not be necessary for its growth. Sediments are necessary in the formation of Black Shale.
The Volga river is the largest river in Europe, so that should be the answer.
Explanation:
When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object's material and the frequency (color) of the light. ... However, because light can travel through space, it cannot be a matter wave, like sound or water waves.
When parallel light rays hit a concave mirror they reflect inwards towards a focal point. Each individual ray is still reflecting at the same angle as it hits that small part of the surface. ... Light rays travel towards the mirror in a straight line and are reflected inwards to meet at a point called the focal point. Opaque objects block light from traveling through them. Most of the light is either reflected by the object or absorbed and converted to thermal energy.
Also, when light is reflected from a mirror, it bounces off at the same angle in the opposite direction from which it hit. ... If the surface is concave, or curved inward, a group of light rays from a distant source is reflected back toward a single location known as the focal point
Letter A. The statement that best describes 21st-century migration flow to the United States is that l<span>arge numbers of immigrants and migrant workers, including skilled and unskilled laborers and many with advanced degrees, are coming to the United States from South and Central America.</span>
