Answer:
Laws of stratigraphy help scientists determine the relative ages of rocks. This law states that deeper rock layers are older than layers closer to the surface. An unconformity is a gap in rock layers. They occur where older rock layers eroded completely before new rock layers were deposited.
Explanation:
The study of rock strata is called stratigraphy. The laws of stratigraphy can help scientists understand Earth’s past. The laws of stratigraphy are usually credited to a geologist from Denmark named Nicolas Steno. He lived in the 1600s.
Hope this helps!
Brain-List?
Answer:
true
Explanation:
blood from heart to body, blood from body to other arteries back to heart and then pumps back into your body again, repeating the process over and over again
Answer:
20%
Explanation:
A species is placed on the endangered species list when its overall population sees a reduction of 20% over a 10 year period or a 3 generation period.
(This is correct, because I got it right on my quiz)
Answer:
"As a molecule moves through the plasma membrane it passes through <em>a hydrophilic layer of phospholipid heads then a hydrophobic layer of phospholipid tails and then another hydrophilic layer of phospholipid heads".</em>
Explanation:
Biological membranes are formed by two lipidic layers, proteins, and glucans.
Lipids characterize for being amphipathic molecules, which means that they have both a hydrophilic portion and a hydrophobic portion at the same time. These molecules have a lipidic head that corresponds to a negatively charged phosphate group, which is the polar and hydrophilic portion. They also have two lipidic tails that correspond to the hydrocarbon chains -the apolar and hydrophobic portion- of the fatty acids that esterify glycerol.
Membrane lipids are arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, while their hydrophobic tails are against each other, constituting the internal part of the membrane.
Through this lipidic bilayer, some molecules can move from one side of the cell to the other, which happens because of concentration differences. When this occurs, molecules must pass through the hydrophilic layer of phospholipid heads then through the hydrophobic layer of phospholipid tails and then again through another hydrophilic layer of phospholipid heads.