Leah is trying to determine how music affects the growth of plants. she hypothesizes that classical music will cause a plant to grow at a higher rate than no music or rap music. she grows nine tomato plants in similar lighting, temperature, and soil. three are exposed to classical music 24 hours a day, three are exposed to rap music 24 hours a day, and three are grown in complete silence. leah measures the growth of the plants every day and finds that the plants all seem to have the same rate of growth. what is missing from leah’s scientific investigation?

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.