Which of the following happens 'first' within an animal response?

a. motor neurons carry directions from interneurons to muscle cells.
b. interneurons receive and process information about the stimulus.
c. sensory neurons pass information about the stimulus to other nerve cells.
d. sensory neurons sense a stimulus.

The correct answer is option (D) Sensory neurons sense a stimulus.

Reflex action is the simplest kind of response to a stimulus by the body. The nerve pathway traveled by the response is called the reflex arc.

In a reflex arc, the receptors in the skin detect the stimulus. The sensory neurons then sense the stimulus and pass it to the relay neurons located in the spinal cord of the central nervous system in the form of electrical impulses. These relay neurons connect the sensory neurons to the motor neurons and process the information about the stimulus. The motor neurons then send the impulses to the effector (part of the body that responds) exhibiting a response to the external stimulus.

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.