Covering various questions and comments:

Nori is made from seaweed. The seaweed most often used to make nori is
in the category (probably Genus) called Porphyra. Seaweed is a
non-technical name generally considered to encompass varieties of
multicellular algae, unlike the microscopic algae that most people
think of when they think of algae. The Porphyra seaweed used in most
commercial nori is farmed.

Kombu is a type of kelp seaweed, which is a different form of algae
from Porphyra.

Nori is made using a technique that is much like papermaking and dates
back at least to the Edo period in Japan.

Nori is best eaten when it is made crisp from a brief exposure to
burning charcoal and then wrapped around one of Masa Takayama's
extraordinary creations.