article_snippet.sent: Today, humans and many other organisms are bilaterally symmetric - we have a clearly discernible top and bottom, and a left and a right.
article_snippet.sent: How we evolved into bilateral creatures, and what we evolved from, has been a cause of some debate.
article_snippet.sent: Today, humans and many other organisms are bilaterally symmetric; we have a clearly discernible top and bottom, and a left and a right - such as depicted in da Vinci's The Vitruvian Man, shown left.