Answer: the selections are on the explanations
Explanation:
BLAST is a commonly-used software package for comparing a query sequence to a database of known sequences.
Delta blast searches a database of pre-constructed PSSMs before searching a protein-sequence database, to yield better homology detection. It first uses RPS-BLAST to align a query sequence to conserved domains in CDD. DELTA-BLAST employs a subset of NCBI's (National Center for Biotechnology Information) Conserved Domain Database (CDD), which performs a sequence database search using a PSSM derived from the aligned domains.