Leeches are soft, squishy animals with long, tube-like bodies that are made of many repeating segments. They contain a heart that pumps blood through their bodies and survive by attaching to other organisms and sucking their blood. What animal phylum do leeches belong in?

arthropods
echinoderms
chordates
annelids

What is the problem in this article? what solution does the article propose?

The diagram below shows the layers of a rock having a trilobite: a rock column labeled rock is shown. the column has three layers. the bottommost layer of the rock has one shaded rhomboid shape, the middle layer has a rhombus with a diagonal along with two identical organisms marked as, trilobite, in the key, the top layer has two semicircles. a key is shown on the right side of the diagram. the shaded rhombus is marked as a, the rhombus with the diagonal is marked as b, the semicircle is marked as c which statement about the rock fossils is true?

Forensic scientists think they know the identity of a skeleton. what rule should they use to select a relative whose dna could be used to try to confirm the identity?