What is observations must be?

Why is scale important with regard to human geography and population? Can a person who ate prion infected food using hands cross-contaminate other things if he touches them after touching food infected with prions if they attached to its hands? What is the best unit of length for measuring the length of a kitchen? Your ridgid orbital sander model R2610 6 in will not hold a hook and latch sanding disc anymore what can you do? How do you ferment rice? Why is carbon dioxide important to the survival of life on earth name one other gas in the earth's atmosphere and explain its importance to living things? What is a good way to find out which plant grows faster in sand soil and cotton? How do you put latitude and longitude onto gps? what metal is a pure element brass copper steel or bronze? What is the energy source that pushes electrons around a circuit? What is the latitude of Darwin? What speed does it take to get to the moon? How does a trout take in oxygen? Which type of protein allows materials to pass through the cell membrane? How can you remove lime scale from concrete? Why do dicots have palisade parenchyma on their leaves? Why when a substance is boiling it stays at 100C? What determines whether a very massive star will become a neutron? How much is 0.73 kg in pounds? Is true of active continental margins?

What is observations must be?