Question

Researchers conducted a two-part investigation to evaluate the enzymatic degradation of polyethylene microplastics by a specialized bacterial strain (*Pseudomonas sp.*).

Experiment 1: Five identical culture flasks were filled with equal volumes of liquid mineral medium and $50.0\text{ mg}$ of standardized polyethylene film. Each flask was incubated at a different constant temperature ($20^\circ\text{C}$, $25^\circ\text{C}$, $30^\circ\text{C}$, $35^\circ\text{C}$, or $40^\circ\text{C}$) while maintaining a fixed agitation speed of $150\text{ rpm}$ and a constant $\text{pH}$ of $7.2$. After 14 days, the percentage mass loss of the polyethylene film was measured for each flask.

Experiment 2: Using the optimal incubation temperature identified in Experiment 1 ($35^\circ\text{C}$), five new flasks were prepared with identical initial media and $50.0\text{ mg}$ of polyethylene film. In this phase, the agitation speed was varied across the flasks ($50\text{ rpm}$, $100\text{ rpm}$, $150\text{ rpm}$, $200\text{ rpm}$, and $250\text{ rpm}$) while keeping temperature, $\text{pH}$, and incubation time constant. After 14 days, the percentage mass loss of the polyethylene film was measured.

Across both experiments, which of the following correctly categorizes the role of the $150\text{ rpm}$ agitation speed in Experiment 1 and the role of the percentage mass loss of polyethylene in Experiment 2?