10. which type of plant tissue is an active site of cell division?
11. usually the plants grow in open spaces and exposed to forceful winds. but they do not break
why?
12. which tissue aquatic plants to float?
13. what is the material present in the bark of stem?
14. name the chemicals that are present at the thickenings of collenchyma cells?

The diagram shows the development of the oocyte and the follicle during the menstrual cycle. identify at which stage in the cycle the hormone levels are at their highest and most active.

The united states uses which source of energy to produce almost 40 percent of its electricity

On a backpacking trip, kenny hikes all day at a steady pace, covering 30 kilometers and burning 4000 calories. at the school track, janelle runs the 100-meter sprint in 13.5 seconds, burning 10 calories. afterward, janelle’s leg muscles are aching and she is breathing hard, while kenny maintains normal breathing all day, even though he burns 400 times more calories than janelle. which two statements offer the best explanation for this phenomenon? a. if the aerobic pathway—cellular respiration—cannot meet the energy demand, then the anaerobic pathway—lactic acid fermentation—starts up, resulting in lactic acid buildup and "oxygen debt." b. aerobic cellular respiration produces more energy, but its use is limited because of lactic acid buildup in the muscles and the resulting "oxygen debt." c. after about 90 seconds of intense exercise, the muscles become depleted of oxygen, and anaerobic respiration can no longer function to produce atp, resulting in "oxygen debt." d. the rate of energy demand determines how the muscles will obtain energy, either from cellular respiration or from lactic acid fermentation if not enough oxygen is present.