A new model explaining this mysterious process suggests the core was created as dribs and drabs of iron percolated inward from Earth's lower mantle, according to a study published Oct. 6 in the journal Nature Geoscience. The mantle is the viscous, rocky layer between the crust and Earth's iron core.
Definition of flash card. : a card bearing words, numbers, or pictures that is briefly displayed (as by a teacher to a class) usually as a learning aid.
Flash first appeared in the Time Spiral expansion, its first appearance in a core set was in Tenth Edition. Although this ability existed before Time Spiral, this is the first time it was used a keyword. The earliest card with Flash is King Cheetah from Visions. Older cards with this ability have received errata to give them Flash. Flash is primary in blue, secondary in green and tertiary in white, black and red.