Why is the timing of tides predictable?

Emotional signs of stress include aches and nausea

So i have a lot of answers answered but it says i still need to answer more questions. why is it doing that? how many questions need to be answered?

Which description best defines the nervous system and its two main branches? a: the message center of the body, split into the autonomic nervous system and the somatic nervous system b: the control panel of the body, split into the central nervous system and the exterior nervous system c: the message center of the body, split into the central nervous system and the peripheral nervous system d: the control panel of the body, split into the brain and the spinal cord