The trilobite in the given image was once found widespread in the ocean. Something changed to limit and finally abolish their
success.
What do scientists use this example as proof of?
Vestigial organisms once had a function in ancient
times.
O Life changes over time.
• The fossil record is incomplete.

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.