According to this evolutionary tree, the archaea and eukaryotes last shared a common ancestor

The correct answer is - 2.5 billion years ago.

Explanation:

The life on the earth has evolved with 3 different lineage namely Bacteria, Eukarya, and Archaea. However the 2 are prokaryotic groups of microbes that lack membrane bound organelles and nuclei.

Recent studies suggested that these two domain, Eukarya and the Arcahea are more close than the bacteria domain. These two domains are shared the common ancestor that probably existed 2.5 billion years ago.

Thus, the correct answer is - 2.5 billion years ago.

b - the respond is innate and varies over time.

good luck!

spiders belong to a group of arachnids.

arachnids have the following traits :

they have two body parts.

they have eight legs unlike insects which have 6 legs.

they have no wings.

these traits distinguish them from insects.

the information that antonio is doubting us the statement that spiders differences are as a result of being first to evolve.

this is because the evolution of one species is independent of the other species.