Vasodilation when you re hot(arterioles dilates so more blood flows through the surface of the skin,vasoconstriction vhen you re cold(arterioles constrict so less blood flows through the surface of the skin)
Am certain that the factor that prevents us from finding fossils from the Precambian era is that Most rocks from that era are deeply buried. The precambrian is the informal name for the large expanse of time preceding the current Phanerozoic Eon. It began with the Earh's Formation about 4.5 billion years ago and lasted until the advent of multicellular life about 542 million years ago.
They are warned about contracting Toxoplasma.
Has varied greatly over time