Can I use an ultrasonic sensor, ir sensor, serial communication with MATLAB on computer and i2c communication with a D6T MEMS thermal sensor simultaneously in Arduino UNO?
simultaneously in Arduino UNO?
No.
You can not do anything simultaneously using an Arduino. However you can do them one after another so fast that it seems like it is happening simultaneously.
No, but you don't need to. You can still check it all quickly enough.