The reason why you cant test the activity of Lipase in test tube 5 is because in test tube 5 the PH is low. This decrease in pH might make it difficult to detect the activity of lipase since the optimal ph of pancreatic lipase is around 8.0. generally high or low PH result to complete loss of activities of most enzymes.
due to the pollution and the evolution by men, the cells in our bodies must lose something in order to get something better, in this case, our ability to avoid cancers, diseases. and sicknesses is lost, but we have evolved into even more intelligent species, thus called HOMO SAPIANS
answer:
The ionic bond is a bond between a metal and a non metal while a covalent bond is one between two non metals
it's very practical, because it's on base 10, so conversion between stuff like meters to kilometer is always just a multiplication with 10 to some power
like 1 km = 1000m (10³m)
or 1 m = 10^-3km = 0.001km
same reason for other SI units.
except time, that's base 60, or 12, or 24. that's more complicated, but there isn't any real competition