GEOLOGY

Detailed explanation-1: -Answer. Answer: It’s generally thought that the evolution of complex life was a rare, once-in-4.5-billion-years event. But new research suggests that conditions were right for complex cells to evolve and die off at least once-or perhaps several times-before our lineage even got started.

Detailed explanation-2: -The simplest level of organization for living things is a single organelle, which is composed of aggregates of macromolecules.

Detailed explanation-3: -A complex organism contains multiple organ systems with different functions. Multiple organisms of a single species may form a group, called a population. Many populations of different species form diverse communities, and communities that share the same geographical space are part of a larger ecosystem.

Detailed explanation-4: -Strange and largely immobile organisms made of tubes were the first complex life on Earth. Appearing 579 million years ago, they thrived on the seafloor for some 37 million years, then vanished – becoming a curiosity we know only from faint impressions in the sandstone fossil record.