What are the two qualities that a medicine must possess?

An 81-year-old man and avid reader had a mild stroke from which he eventually recovered. he did have some residual signs and symptoms, however, such as: - right-sided homonymous hemianopia (i. e. loss of vision on the right half of the visual field in each eye) - alexia ("dyslexia"), the inability to read, which greatly frustrated this man - loss of sensation on the skin on the right side of the body why was this man unable to see the right half of his field of vision?

Waste is deposited into in thin layers which are then compacted and covered with soil.

If human development really does proceed continuously, what value does stage theories of development have?