IF AN ORGANISM IS A MEMBER OF THAR PHYLUM ARTHERPODA ,IS THE ORGANISM NECCESERILY IN THE FAMILY HOMARIDAE?" in

Answer 1

No. Phyla (plural of Phylum) contain a number of classes, orders, and families, so just because it's in the phylum, doesn't mean it has to be in that family, unless it's the only family in that phylum (and it's not - arthropods include insects, crabs, shrimp, spiders, etc.)