Answer
B. three to five days a week
Explanation:
The northern lights, or aurora borealis, offer an entrancing, dramatic, magical display that fascinates all who see it — but just what causes this dazzling natural phenomenon?
At the center of our solar system lies the sun, the yellow star that sustains life on our planet. The sun's many magnetic fields distort and twist as our parent star rotates on its axis. When these fields become knotted together, they burst and create so-called sunspots. Usually, these sunspots occur in pairs; the largest can be several times the size of Earth's diameter.
At the center of the sun, the temperature is 27 million degrees Fahrenheit (15 million degrees Celsius). As the temperature on its surface rises and falls, the sun boils and bubbles. Particles escape from the star from the sunspot regions on the surface, hurtling particles of plasma, known as solar wind, into space. It takes these winds around 40 hours to reach Earth. When they do, they can cause the dramatic displays known as the aurora borealis. [Infographics: How the Northern Lights Work & Anatomy of Sun Storms & Solar Flares]
C and e are the correct choices
Answer:
Tropomyosin
Explanation:
At full contraction, the thin and thick filaments overlap. Tropomyosin is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin.
