B. directional; the curve would shift to the left
During ice ages, larger black bears would have a higher chance of survival and reproduction due to their ability to retain heat and hunt larger prey. This would lead to a shift in the distribution curve towards larger sizes. As the Earth moved out of an ice age and temperatures warmed, smaller black bears would have a higher chance of survival and reproduction due to their ability to dissipate heat more efficiently. This would lead to a shift in the distribution curve towards smaller sizes.