Given the U-shaped graph with mercury concentrations on the y-axis and bird age on the x-axis for both 2005 and 2006, the correct statement is: C Chick age may have a substantial effect on blood mercury concentrations.
The U-shaped graph in Figure 1, depicting mercury concentrations in bird blood relative to age for both 2005 and 2006, suggests a complex relationship. The non-linear pattern implies that chick age significantly influences blood mercury concentrations. The curve may indicate varying exposure sources, bioaccumulation, or metabolic processes affecting mercury levels throughout bird development.
The fluctuating trend contradicts a simple linear correlation, supporting the statement that chick age may have a substantial impact on blood mercury concentrations. This observation underscores the need for nuanced understanding when assessing the relationship between avian age and mercury dynamics in the San Francisco Bay Area, as indicated by the US Geological Survey study.