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In the picture below I noticed there are three circles or holes of some kind ahead of the wing, what are those?

enter image description here
(airliners.net)

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  • $\begingroup$ I totally want I-SMEL in my logbook. $\endgroup$ – HemiPoweredDrone Apr 9 at 6:32
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The three large circles indicated in the question are static port plates. These measure the static pressure of the surrounding air, which is used to measure airspeed and altitude.

MD-80 Decal set with static ports labeled
Original Source

Thanks to a link from Jonathan Walters, here is a closeup of one:

Static port closeup

The four smaller areas in a row along the centerline are the radar altimeter transmitters/receivers. The radar altimeter uses radio waves to determine the aircraft's altitude above the ground. This diagram for the A345 has them further aft, they're in similar configurations on other aircraft.

A345 antenna locations with radar altimeters circled
Original Source

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