<span>The answer is D - the Gravitational attraction between the earth and the moon.
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All elements of a ecosystem work together, the sun provides sun light which plants use photosynthesis for food. Small animals eat the producers aka the plants. Then other animals eat those. And so on if a plant wasn't alive then the whole ecosystem will fail.
Answer:YES
Explanation:A PDA is a type of congenital heart defect. A congenital heart defect is any type of heart problem that's present at birth. If your baby has a PDA but an otherwise normal heart, the PDA may shrink and go away. Some children need treatment to close their PDAs.