CHALLENGES
a call to someone to participate in a competitive situation or fight to decide who is superior in terms of ability or strength
a call to prove or justify something
the administration of an immunogenic or infectious agent to an animal or person, in order to study the resulting immune response or measure the efficacy of a vaccine
invite (someone) to engage in a contest
dispute the truth or validity of
administer an immunogenic or infectious agent to an animal or person, in order to study the resulting immune response or measure the efficacy of a vaccine
a call to prove or justify something
the administration of an immunogenic or infectious agent to an animal or person, in order to study the resulting immune response or measure the efficacy of a vaccine
invite (someone) to engage in a contest
dispute the truth or validity of
administer an immunogenic or infectious agent to an animal or person, in order to study the resulting immune response or measure the efficacy of a vaccine