A top Biden administration medical adviser said Tuesday he did not know why COVID-19 cases continue decreasing in Texas after he and others harshly criticized the state’s governor for rolling back a mask mandate last month. “It can be confusing because you may see a lag and a delay, because often, you have to wait a few weeks before you see the effect of what you’re doing right now,” Dr. Anthony Fauci, one of President Joe Biden’s top COVID-19 advisers, said during an appearance on MSNBC. Texas Gov. Greg Abbott’s mask mandate ended on March 10. “There are a lot of things that go into that. I mean, when you say that they’ve had a lot of activity on the outside like ball games, I’m not really quite sure, it could be they’re doing things outdoors. It’s very difficult to just one on one compare that. You just have to …