A clear plastic ruler is placed across the field of wire of a compound light microscopes row of cells can be seen under low-power magnification (100x) (its science just no science option for subject:)

Skills of homo sapiens were found an excavation. the skulls were preserved because the bodies were frozen. so, these fossils are (blank) fossils.the image shows the evolution of skulls beginning 2 to 3 million years ago. based on the image, modern human skulls(blank) ape skulls.

El amoniaco y el fluor reaccionan para formar tetrafluoruro de dinitrogeno y fluoruro de hidrogeno. segun la reaccion: nh3 + f2 ⇒ n2f4 + hf si reaccionan 5 gramos de amoniaco y 20 gramos de fuor, ¿cuantos gramos de fluoruro de hidrogeno se producen?

This element is in the same family aa lead and it has fewer protons than sodium.