Applying the "if . . then" logic of science (see chapter 1), what are a few of the predictions that arise from the hypothesis that plants evolved from green algae? put another way, how could you test this hypothesis?

Systematics, molecular analysis, and cellular morphology offer enough proof that plants had originated from green algae. In fact, the green algae, red algae, and the land plants come under a similar eukaryotic group, that is, Archaeplastida. The group had descended from an ancient protist that engulfed a cyanobacterium.  

If the plants had originated from green algae than this can be demonstrated by sequencing the genes of both the green algae and plants. If the sequence of gene of plants is closely associated with the gene sequence of green algae, then the hypothesis that the plants had originated from green algae would be certainly true.  

Thus, the mentioned hypothesis can be tested with the help of gene sequencing.  

i believe you meant to say air rather than hair so the answer is below ")

the dead sea, the lowest place on earth at 430 metres (1,410 ft) below sea level, has a correspondingly high typical atmospheric pressure of 1065 hpa.