Can you name 4 things that are invisible but real?

In life we don't see things like: air, gravity, time and even wi-fi but we know they're real. Jesus walked this earth and plenty of people testified to it. He's real. He's not on a cross, he's alive and many testified of seeing him and his nail scarred hands. The only thing that pleases God is faith. Faith in his Son Jesus Christ. Today is the day of Salvation, you may not have tomorrow. The choice is yours and here's your opportunity...

Mark 1:15 And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel.