Delete Unnecessary it … that Phrases

Many it … that phrases are used improperly as transitions or to highlight interesting facts. In many cases, e.g. see the table below, they are irrelevant to the intended purpose and can be omitted altogether.

Delete unnecessary it … that phrases. See other alternatives to shown. Many times, has been is used in place of was.
It is well known that … It has long been known that …
It was shown that … It was found that …
It was reported that … It was observed that …

1 It is well known that African populations exhibit high levels of genetic diversity.

2 African populations exhibit high levels of genetic diversity.

3 It has been reported that the phase of circadian rhythms is earlier in morning-types than in evening-types.

4 The phase of circadian rhythms is earlier in morning-types than in evening-types.