Answer:
The given statement is false.
Explanation:
The mammals can be differentiated into three main groups on the basis of the development of their babies. These three groups are marsupials, monotremes, and placental mammals, which is the largest group. The monotremes refer to the mammals, which lay eggs. The marsupials refer to the mammals, which give birth to young ones that are not developed completely. While in a placental mammal, the development takes place within the body of a mother until and unless its systems of the body start to work on their own.
<span>The correct
answer is 6.</span>
<span>
When we
compare male and female, the prevalence of osteoporosis and the rate of
fractures are much higher in postmenopausal women than in men of the same age.
Because of that, this condition is often called “woman’s disease”.
One of the explications is that women have smaller and thinner bones than men.
Also, estrogen decreases when women reach menopause, which can cause bone loss.</span>
A chromosome contains one long DNA strand.
B.
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.
Answer:
values and beliefs —— example: Americans believe if a person works hard,they will be successful.
Communication example:latin cultures speak spanish.
Food example: hot dogs are an American food.
Religion example: Christianity.
Traditions and customs example: in america,families gather and eat.
