Why does dna need to replication short answer please

Which of the following is true of photosynthesis? a)carbon dioxide is a reactant b)water is a product c)most reactions within this process are exothermic d)oxygen is a reactant

How do tides affect the organisms living in intertidal zones? a. no organisms live in intertidal zones due to the tumultuous environment. b. the mechanical forces of the waves keeps the organisms clean. c. only plants live in intertidal zones because the animals float away with the waves and never return. d. the mechanical forces of the waves can dislodge the organisms from their habitat.

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