Help, I don't know the answers for these

For #25:

Most bivalves are filter feeders, using their gills to capture particulate food such as phytoplankton from the water. The protobranchs feed in a different way, scraping detritus from the seabed, and this may be the original mode of feeding used by all bivalves before the gills became adapted for filter feeding

a

explanation:

a time line cause it goes from 685 to 978