Answer:
1. Height
2. Girth
Explanation:
The woody plants grow in two manners: the primary growth and secondary growth.
The primary growth is considered the type of growth which increases the height of the plant which involves the apical meristem present at the tip of the shoot.
When the height increases up to its maximum length, then secondary growth begins which add tissues to the side that is it increases the girth by adding bark, secondary xylem and phloem.
Thus, Height and Girth is correct.
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.
<span>Root hairs and all active transport mineral ions are used by plants to enable water absorption. The route of the movement of water inside the root would be illustrated through this sequence:Epidermis (outside layer of the roots) --> cortex (ground tissue layer just between the epidermis and the root's vascular tissue) --> endodermis(a layer outside the vascular tissue;responsible for mineral uptake of plants) --> stele( tissues combined inside the cortex) --> xylem (can be primary and secondary, both originates from provascular tissue and vascular cambium,maturing to its inside, respectively) --> phloem (can be primary and secondary too, both originates from provascular tissue and vascular cambium,maturing to its outside, respectively --> cambium(a meristem originating from an apical meristem, gives rise to secondary xylem and secondary phloem. </span>
