Assume you're sound sleeping when the doorbell rings. You get to your feet and walk over to the door, which you open and greet your visitor. Consider the several changes that occur in your body as you awaken and respond to the doorbell. How does the three types of muscle tissue (smooth, cardiac, skeletal) helps in responding to the doorbell?

enhanced global partnerships and exploration capabilities may advance international preparedness for protecting the earth from catastrophic events such as some asteroid strikes, advancing collaborative research on space weather and protecting spacecraft by developing new means for space debris removal.

in addition to being able to metabolize, grow, digest food, and excrete wastes, what other functions must an organism perform if it is to survive? survival also depends on the ability to maintain one's boundaries, to move, to respond to stimuli, and to reproduce. oxygen is a survival need.