Answer:
Adaptations of the alveoli:
Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls - allow gases to pass through. Extensive blood supply - ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.
D. Archaea, bacteria,eukarya
Explanation:
it shields humans and other living things from ultraviolet rays
Answer:
Primary spermatocytes are always diploids
54 × 2 = 108
Explanation:
Primary spermatocytes are diploid (2N), meaning they have a full set of DNA; having a full set of chromosomes. They thus undergo meiosis to form two haploid (N) secondary spermatocytes containing half of the DNA. Therefore, the primary spermatocytes will have 108 chromosomes.