Which is correct about convection currents? A. Is results to formation of valleys and hills
B. It happen in all layers of the Earth
C. It causes Earthquakes
D. It is made possible by heat and pressure

Which one is an advantage of external fertilization a. the offspring are genetically identical to the parents b. more eggs can be fertilzed at one time c. more sperm can be released at one time d. more protection is available for developing plz