I need to know the weighted average please!

In apex! a liquid heated beyond a certain temperature becomes

Acontrol during an experiment. might change remains constant does not exist does change

Ants live on acacia trees in south america. the ants feed on sugars secreted by the trees. the trees provide room for the ants to live. the ants sting any other insect or animal that comes to eat the trees. what type of relationship is this?