What anatomical feature of the veins maintains a unidirectional flow of blood back toward the heart?

Acquired mutations can result from radiation pollution toxins inheritence select all that apply

The picture showed normal blood cells which are around and sickle cells which appear much longer people with sickle-cell suffer from the sickle cell anemia which is inherited diseaseit is caused by a change in gene responsible for production of hemo goblin this type of change is known as an

What should be the strand of complementary dna produced by the strand of dna shown below cgt ata