Choose all the answers that apply. Organisms enter commensal relationships: for transportation for protection for access to food to help other animals to live off of a host

for protection

for access to food to help other animals

to live off of a host

Explanation:

Commensal relationship is a type of symbiotic association between two organisms in which one gets benefits while the other organism gets neither benefit nor harm. This association between organisms provides protection and habitat to one organism and also provides food to them. For example, Nurse plants are the plants that provides protection to seedlings from the weather and herbivores.

amber has allowed scientists to study dna that has been preserved over millions of years.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.