Many scientific discoveries begin with direct observations. which could be a direct observation?
a. ants communicate by airborne chemicals
b. birds navigate by using magnetic fields
c. butterflies eat nectar from flowers
d. fish feel vibrations through special sensors

Among the choices presented above, the statement "Butterflies eat nectar from flowers"  can be called a direct observation. An observation is the term given to the process of  acknowledging and recognizing the facts found around the surroundings. In most times, the observation are expressed by the use of the five senses of man, the sense of smelling, the sense of sight, the sense of tasting, the sense of touch, and the sense of hearing. Observations can either be qualitative and quantitative.

Carbon dioxide is the correct answer