Which statement is true?

a. speed is a scalar quantity and velocity is a vector quantity.
b. speed and velocity are both scalar quantities.
c. speed and velocity are both vector quantities.
d. speed is a vector quantity and velocity is a scalar quantity.
e. speed and velocity are neither a scalar quantity nor a vector quantity.

Idon't really understand this can you me and show your work.☺☺[ chemistry b] subject [ electron transfer in lonic bonds]grade( 12)

Problem page combustion of hydrocarbons such as pentane ( c5 h12 ) produces carbon dioxide, a "greenhouse gas." greenhouse gases in the earth's atmosphere can trap the sun's heat, raising the average temperature of the earth. for this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide.(a) write a balanced chemical equation, including physical state symbols, for the combustion of liquid pentane into gaseous carbon dioxide and gaseous water. (b) suppose 0.350 kg of pentane are burned in air at a pressure of exactly 1 atm and a temperature of 20.0 degree c. calculate the volume of carbon dioxide gas that is produced.be sure your answer has the correct number of significant digits.

What does the xylem do? stores the glucose captures the sunlight absorbs oxygen into the leaf carries water from the roots to the leaves