Menutupnya daun pada malam hari, merupakan gerak
a. seismonasti c. termonasti
b. niktinasti d. fotonasti
Contoh gerak higroskopis adalah
a. pecahnya buah polongan
b. mekarnya bunga pukul empat
c. gerakan sulur pohon labu
d. menutupnya daun putri malu pada sore hari

Environmental impacts on evolution : mastery test

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 of the following is an advantage of using embryonic stem cells in medical research? a. the use of embryonic stem cells is much less expensive than the use of adult stem cells. o b. no living tissue is damaged when scientists use embryonic stem cells. o c. embryonic stem cells are able to differentiate into a wider range of cells than adult stem cells. d. there is no controversy surrounding the use of embryonic stem cells.