“lub” sound is produced after _________ ?

“lub” sound is produced after _________ ?

A. The ventricles are fully contracted
B. The ventricles start to relax
C. The bicuspid and tricuspid valves suddenly close
D. The semilunar valves are closed

Acetabularia is a kind of __________ ?

Acetabularia is a kind of __________ ?

A. Fungi
B. Protist
C. Multicellular alga
D. Unicellular alga

Acetabularia is a genus of green algae in the family Polyphysaceae, Typically found in subtropical waters, Acetabularia is a single-celled organism, but gigantic in size and complex in form, making it an excellent model organism for studying cell biology.