In 2017, some Americans could buy legal marijuana almost as easily as they could order a pizza. Pot shops outnumber Starbucks stores in states like Colorado and Oregon, and medical marijuana delivery services drop the drug off at people's doors in California and Massachusetts.

With marijuana now more accessible — legally — than ever, more researchers are weighing in on its health effects. But that doesn't mean we fully understand the plant or its impacts.

The National Academies of Sciences, Engineering, and Medicine released a massive report in January that gives one of the most comprehensive looks — and certainly the most up-to-date — at exactly what we know about the science of cannabis. The committee behind the report, representing top universities around the country, considered more than 10,000 studies for its analysis and drew nearly 100 conclusions. Many of those findings are summarized below.