If a farmer plants the same crop every year, the soil becomes less fertile. what causes the loss of fertility?

What are the four basic classes of organic molecules how do they differ structurally and functionally

Which of the following describes a negative feedback loop? when the heart rate is too high, the body sends hormones that continually increase the heart rate higher. when a pregnant woman is in labor, the body sends hormones that increase the intensity of contractions, which then increases the secretion of the same hormones. when blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows. when a person is jogging, the body sends hormones that continually decrease the rate of oxygen supply to the legs.

Which event would lead to primary succession of a forest?