Which of the following is not an element The most basic unit of matter
An atom of iron
A molecule of water
A bar of aluminum

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

Why does a plastic bottle that is sealed at a high altitude change it’s shape when taken to lower altitude

Consider the story you just read. all but one of the choices below indicate that something is living.