Which characteristic is used to categorize the different kinds of animal like protists

Why was the sample heated in step 5? describe the chemical principles involved in the reasoning behind this step?

Iguanas need to live in a habitat that is very warm, so the pet store warms their enclosures with "basking lights" which act as an artificial sun. describe how the three methods of thermal energy transfer may take place within the iguana's enclosure.

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain