Given the distribution of the 30 or so animal phyla across the earth's various ecosystems, what would be the most likely habitat for the origin of animals?

Microorganisms aren’t all decomposers; in fact, many act as producers or primary consumers in an ecosystem. how do microorganisms that act as producers benefit the rest of an ecosystem in terms of energy transfer? what about microorganisms that act as primary consumers?

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?

This rapid change in species that rarely leaves behind fossil evidence is referred to as