Provide a structural framework for other tissues. That is your answer <span />
Down syndrome is from chromosome 21 they actually have 3 so a extra
Plate boundaries are the edges where two points meet.
That's D. Viral Reproduction.
It's not A cuz those are not bacteria
It's not B cuz diffusion deals with passive transport across membranes
It's not C cuz gamete formation deals with sex
Answer: 4. Problem solver
Explanation: you're working to fix a known problem