BIO question~~~~~~~~~~~

1. A student found that the rocks on the side of a pond were covered by a layer of green plants of millimetres thick.These plants are propaply
(1) ferns (2)mosses (3)algae
A.(1)and (2) ONLY
B.(1)and (3) only
C.(2)and(3)only
D.(1),(2)and(3)

2.Which of the following feature(S) is(are)requires for classifying a plant as an alga?
(1)not differentiated into tissues
(2)with chlorophyll
(3)filamentous in shape
(4)living in fresh water
任選,plz explain~~~thz~~~