Describe how a triglyceride molecule is formed.

Table 5 shows some properties of four fatty acids.

Figure 10 shows diagrams of these fatty acids.

Put a tick (✓) in one box that contains correct information about one of these fatty acids.

☐ Caprylic acid is an unsaturated fatty acid represented by diagram L.

☐ Linoleic acid is a saturated fatty acid represented by diagram N.

☐ Palmitoleic acid is an unsaturated fatty acid represented by diagram K.

☐ Stearic acid is a saturated fatty acid represented by diagram M.

The percentage of saturated fatty acids compared with unsaturated fatty acids found in lipid stores in seeds differs in different populations.

Scientists investigated two populations of the plant, Helianthus annuus.

The scientists grew young plants from seeds collected from each population. They placed the seeds on wet tissue paper so that the root growth was visible.

They grew seeds from each population at two temperatures:

• warm temperature of 24 °C • cool temperature of 10 °C

After 10 days, the scientists measured the length of each root.

Table 6 shows some of the properties of the two populations and the scientists' results.

The mean ±2 × standard deviation includes 95% of the data.

The scientists used a data logger to measure the length of the root rather than a ruler.

Suggest one reason why they used a data logger and explain why this was important in this investigation.

It is known that:

• during respiration saturated fatty acids yield more energy than unsaturated fatty acids • saturated fatty acids have higher melting points than unsaturated fatty acids • lipases in seeds act more rapidly on liquid substrates.

Use this information and Table 6 to show how each population is better adapted for its natural environment when compared with the other population.

Although these two populations are completely separate and show genetic variation, they are both called Helianthus annuus.

Explain why they are both given this name.