In sea-floor spreading, molten material rises from the mantle and erupts
a. along the edges of all the continents.
b. along mid-ocean ridges.
c. in deep-ocean trenches.
d. at the north and south poles.

A ridge forms along a crack in the oceanic crust. At a mid-ocean ridge, molten material rises from the mantle and erupts. The molten material then spreads out, pushing older rock to both sides of the ridge. ... This process, called sea-floor spreading, continually adds new material to the ocean floor.

its 42

i say its d?

humans are now responsible for causing changes in the environment that hurt animals and plant species. we take up more space on earth for our homes and cities. we pollute habitats. human activity often changes or destroys the habitats that plants and animals need to survive.