A) From the results in the table, it is evident that increasing the concentration of sodium chloride has a negative effect on spinach seed growth. As the concentration of sodium chloride increases f

a) From the results in the table, it is evident that increasing the concentration of sodium chloride has a negative effect on spinach seed growth. As the concentration of sodium chloride increases from $0.00 \text{ mol/L}$ to $0.18 \text{ mol/L}$:

• The percentage of spinach seeds that started to grow roots decreases significantly, from $99.98\%$ to $54.0\%$.
• The mean root length also decreases consistently, from $17.70 \text{ mm}$ to $7.60 \text{ mm}$. This indicates that higher concentrations of sodium chloride inhibit both the germination rate and the subsequent growth of roots in spinach seeds.

b) Apart from a ruler, two other pieces of equipment one would need to determine the rate of growth in roots are:

1. A stopwatch or timer to accurately measure the time intervals over which growth occurs.
2. A magnifying glass or microscope to observe and measure the small roots more precisely.