The answer is 'Cambrian' explosion. This took place approximately 541 million years ago. 'Explosion' refers to the evolution of a large range of new major animal phyla. Scientists know this by the large number of diverse fossils from this period. Prior to this period, organisms were single-celled, but over the Cambrian Explosion, lasting about 80 million years, life forms diversified rapidly to resemble the life forms existing today.
Simple squamous epithelium
Answer:
notochord, a dorsal hollow nerve cord and pharyngeal slits.
Electrons are the smallest of the three particles that make up atoms.
Please correct me if I'm wrong!! I'd be happy to fix it!! :)
