The correct answer is option C, that is, behavioral isolation.
The phenomenon of behavioral isolation takes place when two populations possess the tendency of interbreeding, but exhibit distinctions in courtship rituals or other kinds of behavior. For example, the western and eastern meadowlarks are very identical birds whose habitat overlap in the middle of the United States.
However, the members of the two species will not mate with each other, possibly as they use different songs in order to fascinate males. The eastern meadowlarks will not respond to the songs of western meadowlarks, and vice versa.
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:
Technology because we don't have the necessary technology to explore the parts of space and for all we know we don't even know what the universe actual looks like or if there are alternate universes but as technology advances we will know. Explanation:
