What is the significance of each of the following in the study of astronomy: (a) dark matter (b) dark energy (c) 21 cm radiation

Which statement explains what upwelling causes? a. upwelling causes tides to rise and fall. b. upwelling causes changes in the direction of currents. c. upwelling causes nutrients, minerals, and tiny organisms to rise. d. upwelling causes currents in the pacific ocean to change direction. i think the answer is c.

Astate's representation in the u.s. senate is based on a) equal representation. b) the state's population. c) the state's electoral votes. d) the size of their major cities.this independent regulatory agency was created in 1974 to oversee and regulate the financing of political campaigns in the united states. a) warren cthis independent regulatory agency was created in 1974 to oversee and regulate the financing of political campaigns in the united states. a) warren commission (wc) b) federal election commission (fec) c) equal opportunity commission (eoc) d) securities and exchange commission (sec)

The meseta in spain is a a. navigable river b. castle c. coastal plain d.plateau