3. The building block for lipids is isoprene or 2-methyl-1,3-butadiene. Draw it below. Now look up limonene, how many isoprene units make up this natural product? 4. Look up the following molecules: chlorophyll a, -carotene, and -cryptoxanthin. What types of functional groups can be found in each molecule. Based on Figure 4 of the introduction, which rank the three molecules in decreasing polarity