Final answer:
Pine wood has a density of approximately 0.7g/cm^3, which matches the description given in the question, making it the correct answer. Therefore, the correct answer is b) Pine.
Step-by-step explanation:
When considering the density of wood, we examine the mass per unit volume, or in other terms, how much a cubic centimeter (cm3 or cc) of the wood weighs.
To answer your question - which kind of wood has a density of 0.7g/cm3 - we can rule out some options based on their known densities. For example, balsa wood is known to be very light with a density of 0.15 g/cm3, so it cannot be the correct answer.
Oak and cherry woods typically have higher densities, and pine wood falls into the middle range. Between these options, pine wood is the one that has a rough density of 0.7g/cm3, making it the correct answer to your question.