Which features of how seedless land plants get sperm to egg are the same as for some of their algal ancestors?

Flagellated sperm swims to egg in water drop.

Explanation:

The seedless land plants reproduce through the production of unicellular haploid cells which disperse easily because it is light weight. The male antheridium releases sperm. This sperm has flagella which is use for swimming in water or moist environment to the female archegonia to fertilize it and produce embryo. This embryo develop in the sporophyte.

The algae sperm also have flagella for swimming in water to meet and fertilized the egg to produce embryo.