Worldwide, there are 107 boy babies born for every 100 girl babies. This skewed ratio is partly due to sex-selective abortion and "gendercide," the killing of female infants, in countries such as China and India where males are more desired. But even discounting those factors, the completely natural male-to-female sex ratio still hovers around 105:100, meaning that women are inherently more likely to give birth to boys. Why?
Several factors influence whether a sperm containing a Y sex chromosome or one containing an X chromosome will be first to fertilize an egg, including parental ages, their environmental exposure, stress, the stage in the mother's ovulation cycle and even whether she has had children previously; all these forces combine to set the average sex ratio at fertilization at 105:100.
Answer:
69700000
Explanation:
6.97* 10 to the power of 7 = 69700000
Answer:
sexual reproduction there i didn't want to type that
Answer:
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."
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.
Explanation:
It is important to consider that Kenny hikes all day but at a steady pace, whereas Janelle runs very fast. So Kenny's case, the supply of oxygen is sufficient to maintain aerobic respiration within the muscle cells. During this process only CO2, Water, and ATP are produced; therefore, there is no oxygen debt. We should keep in mind that the body shifts to anaerobic metabolism only when the supply of oxygen is limited.
In Janelle's case, running fast would need energy at higher rates and the supply of oxygen would not be sufficient to generate a high amount of ATPs. Therefore, to compensate for this deficiency, cells will start fermenting glucose to lactic acid and produce ATP and maintain energy demands. This lactic acid causes fatigue and this is why Janelle has aching and breathing hard. Breathing hard is also automatic reflux to inhale more oxygen and meet oxygen demands but even breathing hard would not be able to make it and the body will shift to anaerobic respiration automatically.