How do composite volcanoes get its layered interior?

Why do oceanic plates tend to subduction when colliding with a continental plate

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

"does stress during a woman's first trimester of a pregnancy affect the infant's birth weight? " is a