Agonist/antagonist
Agonist are drugs that bind and activate a receptor with effecting the response.If the effect results in maximum response it is considered as full agonist. However if the drug that binds to the receptor results only into partial efficacy in relation to the full activation of the receptor, this is considered as partial agonist.
Antagonist are drugs that blocks a biologic response of a hormone or another drug. They usually have affinity to the receptors but has no efficacy. This drug will just inhibit the activation of the receptors by the aganist.
Annelids have neither an external or an internal shell. Examples of annelids are
earthworms and leeches.
The correct answer is D.
The domain is the broadest category in the classification of living organisms. All the living organisms are placed in three domains, which are archaea, bacteria and eukaryotes. The prokaryotes are separated into two groups, that is archaea and bacterial based on the differences in their 16S rRNA genes. Amoeba is classified as an eukaryotes because, its cell is more developed than that of bacteria.
