Answer:
I think it is the variable.
Explanation:
<span>There are numerous proteins in muscle. The main two are thin actin filaments and thick myosin filaments. Thin filaments form a scaffold that thick filaments crawl up. There are many regulatory proteins such as troponin I, troponin C, and tropomyosin. There are also proteins that stabilize the cells and anchor the filaments to other cellular structures. A prime example of this is dystrophin. This protein is thought to stabilize the cell membrane during contraction and prevent it from breaking. Those who lack completely lack dystrophin have a disorder known as Duchene muscular dystrophy. This disease is characterized by muscle wasting begininng in at a young age and usually results in death by the mid 20s. The sarcomere is the repeating unit of skeletal muscle.
Muscle cells contract by interactions of myosin heads on thick filament with actin monomers on thin filament. The myosin heads bind tightly to actin monomers until ATP binds to the myosin. This causes the release of the myosin head, which subsequently swings foward and associates with an actin monomer further up the thin filament. Hydrolysis and of ATP and the release of ADP and a phosphate allows the mysosin head to pull the thick filament up the thin filament. There are roughly 500 myosin heads on each thick filament and when they repeatedly move up the thin filament, the muscle contracts. There are many regulatory proteins of this contraction. For example, troponin I, troponin C, and tropomyosin form a regulatory switch that blocks myosin heads from binding to actin monomers until a nerve impulse stimulates an influx of calcium. This causes the switch to allow the myosin to bind to the actin and allows the muscle to contract. </span><span>
</span>
Answer: A - Rods are more numerous than cones
Explanation: Rods are found everywhere in the retina except the fovea (a tiny pocket in the retina where just about all of the cones are located).
B. The macula lutea is another word for fovea, no rods are found there.
C. Rods are utilized in low-light conditions and are not <em>sensitive</em> to wavelengths of light.
D. Cones are responsible for perceiving color and not rods.
E. The main function of the rods is to help us see in low-light conditions (scotopic vision), so this answer would be incorrect.
The mitochondria is the powerhouse of the cell because it produces ATP, which is energy.
