At the onset of the embryonic period, the appear(s). it will eventually become the neural tube. stem cells spinal cord primitive streak placenta

The energy needs of a human population are not affected by

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a. earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c. earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.

Which of the following typically characterizes a tropical rainforests