+50 pts how can you tell that algae filaments are composed of several cells rather than just one?

Non-scientific method:

Well, an easy way is observing the filament under a microscope: if it contains one cell it's unicellular and if it contains more than one cell it's multicellular.

Scientific method:

Filamentous algae are, in principle, single-celled. But, sometimes they can form colonies and evolve to be multicellular. But still, if they just form a colony they'll still be unicellular until they start changing.  

Unicellular.

Hope it helped,

BioTeacher101

option number one would be youre best option

the answer is c a tornado