Energy trasfer and temapature transfer in a pool

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

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?