Fill in the missing interactions and species on this table

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

we would need to see the picture to answer it

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.

thinking it would be d not too sure but i think it's right