Please explain apraxia to me?

Apraxia: Apraxia is a brain/nervous system disorder that makes a person unable to do tasks or movements when asked - even though they can understand the request and want to do them. Their muscles function, and they may even have learned to do the task before. Possible causes include stroke, brain tumor, dementia, neurodegenerative condition, and traumatic brain injury.

Apraxia: Motor disorder caused by damage to Posterior Parietal Cortex of the brain leading to difficulty with motor planning.

Motor problem: Apraxia is a motor disorder in which a person has the requisite individual pieces needed to carry out a complex motor activity, but cannot put them together in a coordinated manner to carry out the task.