Answer: 1) Brain abnormalities
Explanation:
Mercury exposure during pregnancy can lead to brain abnormalities in the unborn child. Mercury is a neurotoxin, meaning it can interfere with the development and function of the nervous system. In pregnant women, mercury can pass through the placenta to the developing fetus, where it can accumulate in the fetal brain and nervous system. This accumulation of mercury can disrupt normal brain development, potentially leading to various brain abnormalities, including impaired cognitive function, learning disabilities, and developmental delays. Therefore, it is crucial for pregnant women to be cautious about their consumption of fish high in mercury to minimize the risk of adverse effects on their unborn child's brain development.