Question

which two characteristics do all animals have?
they are symmetrical and heterotrophic.
they are heterotrophs and have a backbone.
their cells have a nucleus and membrane - bound organelles.
they have a backbone, and their cells have membrane - bound organelles.

Explanation:

• Animals are eukaryotes, so their cells have a nucleus and membrane - bound organelles.
• Not all animals are symmetrical (e.g., some sponges).
• Not all animals are vertebrates (have a backbone), as there are invertebrates.
• While animals are heterotrophs, the key universal cellular characteristic is having a nucleus and membrane - bound organelles.

Answer:

Their cells have a nucleus and membrane - bound organelles.