The answer is "the ice-caps" from the north and south pole.
Answer:
sahi bol rahi hai ye ladki
Explanation:
I also think ,u lack ur sleep
Answer:
Ozone
Explanation:
Ozone is considered a pollutant in the troposphere, but in the stratosphere it is essential to life on earth because it absorbs biologically harmful UV radiation. The mesosphere and the thermosphere are two additional atmospheric layers above the stratosphere.
Answer:
texture
Explanation:
Elements have been classified into three categories namely; metals, non-metals and metalloids. This classification was done based on certain characteristics or properties possessed by each element. Some of the characteristics used are: lustre, malleability, conductivity, melting point, boiling point etc.
- Metals are very good conductors of heat and electricity whereas metalloids and nonmetals are not.
- Metals and metalloids shine when polished i.e. they are lustrous, whereas nonmetals don't
- Metals are malleable i.e. can be beaten into sheets.
Texture is not a property used to classify metals and metalloids.
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.
