Answer:
a. Eukaryotes, and b. multicellular.
Explanation:
Eukaryotic organisms are those organisms that have cells with membrane bound organells, such as nucleus, mitochondria, and glogi body.
Both plants and animals are multicellular (made up of more than one cell) eukaryotic organisms that belong to domain Eukarya.
However, plants are phototrophic organisms that make their own food, while animals are heterotropic that depend on other organisms for food. An another difference between plants and animals is motility as plants are generally non-motile, while animals are motile.
Thus, options (a) and (b) are the correct answers.
