Sound waves<span> coming from farther above, where it is warmer, will experience a refraction. The change in speed from the warmer </span>air<span> to the cooler </span>air<span> causes a bending effect, as the </span>sound travels<span> downward.</span>
D. the number of mates on the island
their appearance changes cause different birds breeding together can make an impact of how the bird looks
Omg going to say A I could be wrong
Answer:
The correct answer is 3: "<em>High levels of Ca2+ are expected to be found </em><em>within the sarcoplasmic reticulum</em>".
Explanation:
Muscular contraction is a highly regulated process that depends on free calcium concentration in the cytoplasm. Amounts of cytoplasmic calcium are regulated by <u>sarcoplasmic reticulum</u> that functions as a storage of the ion.
When a nerve impulse reaches the membrane of a muscle fiber, through acetylcholine release, the membrane depolarizes producing the entrance of calcium from <u>extracellular space</u>. The impulse is transmitted along the membrane to the sarcoplasmic reticulum, from where calcium is released. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. The calcium channel in the sarcoplasmic reticulum controls the ion release, that activates and regulates muscle contraction, by increasing its cytoplasmic levels. When <em>calcium binds to the troponin C</em>, <em>the troponin T alters the tropomyosin by moving it and then unblocks the binding sites,</em> making possible the formation of <em>cross-bridges between actin and myosin filaments.</em> When myosin binds to the uncovered actin-binding sites, ATP is transformed into ADP and inorganic phosphate.
Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Answer:
D
Explanation:
Many animals influence and contribute to ecosystem services. As pollinators, how do bees ultimately contribute to direct ecosystem services? (1 point)
O Bees pollinate plant species that contribute to the carbon cycle.
O Bees pollinate plant species that humans admire in nature.
Bees pollinate plant species that produce oxygen that humans need.
O Bees pollinate plant species that produce food.
