The muscular system and the skeletal system are two different organ systems, but they’re often referred to jointly as the musculoskeletal system. Why do you think the word musculoskeletal exists? What similarities in functions do you think the muscular system and skeletal system have?

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

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 

you can have just about every answer you can think of