Melatonin is secreted by
A. the hypothalamus during the day
B. the pineal gland during the night
C. the autonomic nervous system during the winter
D. the thyroid gland during cold seasons

The zone, which exists from a depth of 0 to 600 feet, is home to the majority of ocean life.

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.