.45 auto, if, by "G36", you're referring to the Glock 36. 5.56x45 if you're referring to the Heckler & Koch G36 rifle.

Yes; as an assault rifle, the Heckler & Koch G36 has select fire capabilities, and can fire in both semi-automatic and fully-automatic modes.

If you're referring to the Heckler & Koch G36, yes, it certainly can. It can put holes in people, too.

The Guns that the Portuguese army use are as follow's.

Handguns

Walther P38

SIG P228

Heckler and Koch USP9

Rifles and Carbines

Heckler & Koch G3

Heckler & Koch G36

Heckler & Koch HK 417

IMI Galil

Heckler & Koch MSG-90

AI AWSF

AI AWSM

AI AW50

Barrett M95

Barrett M82A1

Sub-Machineguns

Brügger & Thomet MP9

Heckler & Koch MP5K

Heckler & Koch MP5A5

Heckler & Koch MP5SD6

IMI Uzi

Shotguns

Mossberg 500

Benelli M3

Franchi SPAS 15

Machine Guns

MG3

Heckler & Koch HK 21

FN Minimi

Heckler & Koch MG4

Heavy Machine Guns

FN M3M

Browning M2HB

Grenade Launchers

HK79

M203

Heckler & Koch AG36

ARWEN 37

Milkor MGL

Mortars

120mm Tampella B

81mm L16 A2 m/86

60mm Soltan

60mm FBP m/68

Missile Launcher's

M72 LAW

Carl Gustav M3

MILAN

TOW

Heckler & Koch G3 Steyr AUG M-16 AK-47 Heckler & Koch MP5 Heckler & Koch MP5K-PDW Heckler & Koch G3 Steyr AUG M-16 AK-47 Heckler & Koch MP5 Heckler & Koch MP5K-PDW