Training can help improve all of the following skills except:

The assertion that training can improve all of the listed skills except for visual ability is based on the understanding of the nature of these skills and how they are developed.

Visual ability encompasses a broad range of perceptual and sensory functions that are often fundamental but can be more inherently linked to biological or genetic factors. While training can enhance specific facets of visual skills, such as hand-eye coordination or visual processing in certain contexts, substantial improvements in basic visual ability might not be as influenced by training compared to cognitive skills like memory recall, mathematical reasoning, and spatial orientation.

In contrast, memory recall can be significantly enhanced through various training techniques, such as mnemonic devices and rehearsal strategies. Similarly, mathematical reasoning can improve through practice, problem-solving exercises, and instruction. Spatial orientation skills often benefit from both practice and specific training environments that challenge an individual's ability to navigate or visualize space effectively.

Thus, the distinction lies in the more systemic nature of visual ability compared to the more trainable cognitive skills in the other options.