Please help is for today

Which best describes the digestive system of arthropods? a incomplete, two openings b complete, one opening c two-way, one opening d one-way, two openings

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

Biology ! the conversion of inorganic carbon to organic carbon by plants during photosynthesis is known as _[blank]_. filtration immigration reabsorption primary production