Tectonic plates are able to move because of

a) sliding of the continents toward the oceans

b) gravitational differences between different parts of earth as it revolves around the sun

c) relatively dense oceanic crust sinking into the weak asthenosphere at subduction zones

d) the sinking of the continents into oceanic crust at the mid-ocean ridge

Hydrilla (hydrilla verticillata) is an invasive aquatic plant and one of the most serious aquatic pests in florida. hydrilla has already been introduced to hundreds of bodies of water throughout florida, hydrilla is difficult to control because it grows rapidly and survives in many different water depths and conditions. hydrilla • describe how hydrilla affects native plant and animal species. include both a biotic and an abiotic limiting factor. • suggest one biotic and one abiotic recommendation that could slow the spread of hydrilla