How many banner and Interstitial are allowed per screen of app

Kreator Camp Ads
#1

how many banner and Interstitial are allowed per screen of app in admob

#2

in AdMoB, one banner per screen at the bottom of screen & 1 interstitial ad but make sure you show it between 2 activities

#3

1 banner and Interstitial (one screen)

#4

2 activity means ?