Veins are the correct answer. Sills are a slab of stone, Joints are artificially made, and Dikes are ditches or walls to prevent flooding.
This would be true.
The reason why this answer would be true is because a fossil's position in the rock layers determine how long they died and were preserved. If the fossils were right next to each other, then that means both organisms were preserved at the same time.
Answer: The correct answer is Francium and Fluorine.
Explanation:
The most vigorous chemical reaction will occur between the most reactive metal and most reactive non-metal.
Reactivity of metal is defined as the tendency of elements to loosing electrons easily. Reactivity of metals decreases as we move from left to right and increases as we move down in the group. Hence, the most reactive metal is Francium.
Reactivity of non-metals is defined as the tendency of the element to gain electrons easily. Reactivity of non-metals increases across a period and decreases as we move down in a group. Hence, the most reactive non-metal is Fluorine.
Therefore, the most vigorous chemical reaction will occur between Francium and Fluorine.