Drag each tile to the correct box. Arrange the tiles to show the sequence of the steps in a scientific investigation. make an observation ask questions construct a hypothesis test the hypothesis analyze the results and make conclusions communicate the results ↓ ↓ ↓ ↓ ↓

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

its probably to later but whats the question

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.