Are there any parts of the human body that get oxygen directly from the air and not from the blood?

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

How does pregnancy begin? a) a placenta forms in the uterus b) a sperm reaches an egg in the fallopian tubec) the blastocyst differentiates into two cell types d) contractions begin in the uterine wallapex

The law of states that traits are passed from parents to offspring independently of one another.. true or false