Which of these organisms is supported by tubes made of cellulose?
a. elephant
b. crab
c. beetle
d. tree

Type the correct answer in each box. use numerals instead of words. if necessary, use / for the fraction bar. the following chemical equation shows the combustion of ethane. balance the equation by filling in the coefficients. c2h6 + o2 → co2 + h2o

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates

Ascientific idea becomes valid when it is what?