Burp Suite Security Testing Of Web Applications
It is observed that the same gas is adsorbed to different extents by different solids at the same temperature. Further, as may be expected, the greater the surface area of the adsorbent, greater is the volume of the gas adsorbed. It is for this reason that substances like charcoal and silica gel are excellent adsorbent because they have highly porous structures and hence large surface areas.
I shop regularly online and maybe only half of the gateways use OTP (SMS verification) since the effective date, the other half still isn't and this is for domestic purchases. I can't recall using OTP for international purchases, not even once. I can still easily shop online just by providing the usual: credit card number, name on the card (sometimes not needed), expiry date (not always needed either) and CVC, no SMS or any other kind of verification is required, let alone a phone call (this latter sounds a lot like Latin America to me). I can't really tell, what's the case in other countries, but as Gogol mentioned it too above, OTP/3D secure wasn't a requirement for the Digitalocean purchase he just made and he is from India (i think), it was an international purchase.