which is more likely to be the cause of down syndrome the egg or the sperm?
The egg
Given what we know, we can confirm that as scientists study fossil records, they can learn much about the species, such as the traits and activities of the organisms in question.
<h3>What does each fossil type teach us?</h3>
- Trace fossils such as footprints can teach us about the activities of the organisms.
- Meanwhile, scientists will use body fossils to learn about the specific traits of early organisms.
- Body fossils can at times also provide insight as to the diet of the species.
Therefore, we can confirm that scientists will use body fossils to learn more about the traits and diets of early organisms while using the uncovered trace fossils to track the activities of these organisms.
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Answer:
Individuals in a population are naturally variable, meaning that they are all different in some ways. This variation means that some individuals have traits better suited to the environment than others. ... Through this process of natural selection, favorable traits are transmitted through generations.
Answer:
When a muscle cell contracts, the myosin heads each produce a single power stroke.
Explanation:
In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed into ADP and inorganic phosphate which is liberated. Myofilaments slide impulsed by chemical energy collected in myosin heads, <u>producing a power stroke</u>. The power stroke initiates when the myosin cross-bridge binds to actin. As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
