Round 3 - Judge Edith

...because both are required for a healthy heart . -- Requiem
...because both are required for intergalactic travel . -- Whistway
...because neither sellotape a Super Size meal in my head . -- MikeJeggo
...because both are as lonely as one would expect . -- Bobacus
...because both have been mistaken for Concrete Cows by George W Bush . -- DouglasReay
...because both are found in my room . -- AlexChurchill