Which are true about the what are true about the embryonic and fetal stages? Check all that apply.
The embryonic stage is the third to the eighth week after fertilization,
The fetal stage is the ninth to the thirty-eighth week after fertilization,
In the embryonic stage, the number of cells increases.
In the fetal stage, the number of cells remains the same.
An embryo is an early developmental stage that ends when all organs are present.

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.

How is the carbon cycle related to global warming ?

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.