Answer:
<em>T</em><em>he photograph shows</em><em> soil layers</em><em><u> </u></em><em><u>.</u></em><em><u>T</u></em><em><u>he darkest layer of the soil at the top of the photograph</u></em><em><u> is</u></em><em><u> The Horizon</u></em><em><u>.</u></em>
Explanation:
Called the A horizon, the topsoil is usually the darkest layer of the soil because it has the highest proportion of organic material.
Answer:
Among these adaptations are: streamlined bodies for efficient movement through water; forelimbs modified into flippers to aid in steering; hind limbs internalized remnants reducing drag; tail positioned horizontally to achieve a powerful up and down propulsion; hair replaced with under-skin blubber to provide warmth ...
Explanation:
Answer:
The source of Calcium (Ca⁺⁺) for the skeletal muscle cells is the sarcoplasmic reticulum, the main store of intracellular Ca⁺⁺.
Explanation:
Calcium (Ca⁺⁺) is an ion that plays an important role in muscle contraction, a process that requires high cytoplasmic concentrations of this ion to promote myofibrillary activity.
The sarcoplasmic reticulum (SR) -equivalent to the endoplasmic smooth reticulum- is an organelle that regulates the contractile activity of skeletal muscle. The two terminal cisterns of the SR attach to the T-tube, forming a triad, which surrounds the myofibrilla.
Once the muscle cell receives the signal to contract, the Ca⁺⁺ channels are opened and allow Ca⁺⁺ to enter the cell, promoting the exit of this cation from the SR and increased its cytoplasmic levels. This stimulates muscle contraction.
I don't know if this question is missing some multiple choice options that go along with it, but...
One plate will subduct (go under the other plate), creating a trench or subduction zone. The other plate goes over the subducted plate, creating raised ground. This is how mountains and volcanoes are made.
