Final answer:
a) Seed germination decreases with increased soil salinization. The hypothesis states that seed germination decreases with increased soil salinization based on the experiment results.
Step-by-step explanation:
The hypothesis that states the impact of increasing soil salinization on seed germination based on the results of this experiment is:
Option a) Seed germination decreases with increased soil salinization.
This hypothesis is supported by the trend mentioned in question 2 above, which indicated that the germination rate decreased as the salinity of the soil increased. Therefore, it can be inferred that increasing soil salinization has a negative impact on seed germination.