1. If a wave is traveling across a boundary from a material of low density to high density will the velocity of the wave increase or decrease?

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg 

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.

well, i believe that the answer is 2. : 3