[Solved] _________ can be an effective means of protecting a local system or network of systems from network based security threats while at the same time affording access to the outside world via wide area networks and the Internet. Rhyniophyta: An extinct group of early vascular plants from the Silurian and Devonian periods. Megafossils: Larger fossilized remains of organisms, such as bones or plant stems, that are easily visible to the naked eye and provide significant evidence of life from the past. Dichotomously Branched: A branching pattern where each branch divides into two parts at a certain point. Megaphylls: Leaves with a highly branched vascular system, characteristic of the majority of vascular plants, offering increased efficiency in photosynthesis.