What does the arrow of the food chain mean

Which statement is true about the cell theory? a) it is well-supported by evidence. b) it is unchangeable and permanent.

Prior to the development of dna fingerprinting, blood type could be used to determine possible parentage. although it might prove someone was not a parent, it could not show if someone was positively the parent, only that he or she might be a parent. which of the following is a true statement that can be made about parentage based on blood typing?

How does photosynthesis show the conservation of mass and energy?