Air can be considered a mixture. which statement does not explain why?

1) these are barrel shaped microtubules in most animal cells, that organize the spindles during cell division

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

Iron (3) oxide will decompose in the presence of hydrogen gas and heater to produced iron and digydrogen monoxide white a balanced chemical equation