Pointâofâsale transactionsâi.e., swiping a card at the time of purchaseâsecurely encrypt the. credit card data. Cards placed on file for future transactions, such as for express checkâout, use. tokens to access card data.
The outermost layer of Earth is the atmosphere. I say the atmosphere is the outermost layer, because it is as much a part of the of our planet as the atmosphere of other planets is a part of their definition.
The outer layer is an incomplete maternofetal barrier that may have an immunoprotective function. Figure 4-2. Schematic view of a placental unit and the components of identified segments. (From Novak RF. A brief review of the anatomy, histology, and ultrastructure of the full-term placenta.