Which level of organization is formed when a group of organs work together to perform complex functions? molecule organ organ system tissue

The observations of hooke and van leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory? a. the cell theory stating that all living things are composed of cellsb. the theory of spontaneous generation, which held that life forms could arise spontaneouslyc. the theory of chemotherapy, or use of antimicrobials to destroy pathogenic organismsd. the germ theory of disease and causative agents

The kind of fertilization found in the majority of aquatic animals is (internal or external) fertilization.

Some mining processes involve removal of large areas of earths surface in the mined region this practice causes severe environmental damage by allowing which natural process to accelerate in the affected areas? a. precipitation b. erosion c. migration d. condensation