Explain specified sensors

Explain how do the DH11, BMP180 work in terms of physical functioning  (for example:  the pressure sensor is relying on a resistive element whose resistance changes with change in force, the humidity sensor…. etc etc)

Explain physical functioning in terms of finding temperature and humidity for DHT11

Explain physical functioning in terms of finding atmospheric pressure and Altitude for BMP180

Also explain whats the job of the ESP8266 (WIFI module) and how does it work (I am using Arduino Uno as the microcontroller if that helps making your explanation relevant to my work)