If the inner lining of the air sacs neither thin nor highly vascularized, then it can be inferred that AIR SACS ARE CANNOT BE THE SITES OF GASEOUS EXCHANGE BETWEEN AIR AND BLOOD. Air sacs are generally lined with mucus and surrounded with blood capillaries.
In case of birds, air sacs play an important role in respiratory system.
Answer:
you....your not asking anything?

Last option: Preserve an ecosystem

• The establishment of a bird reservation is a way to preserve an ecosystem because reservation provides suitable environment to organism. A healthy ecosystem means large number of biodiversity.
Answer: Haploid number
In normal humans, sex cells contain the diploid number of chromosomes
Explanation;
Human somatic cells or body cells are diploid such that they contain two sets of 23 chromosomes which gives a total of 23 chromosomes. Examples of somatic cells in the body that are diploid include, epithelial cells, somatic cells, liver cells, blood cells, nerve cells, etc.
However, mature sex cells are haploid, which means they have one set of 23 chromosomes which means they have 23 chromosomes. Sex cells are the results of meiosis type of cell division in which a diploid cell divides to form four daughter cells that are haploid.
Answer:
Agroforestry is a collective name for land-use systems and technologies where woody perennials (trees, shrubs, palms, bamboos, etc.) are deliberately used on the same land-management units as agricultural crops and/or animals, in some form of spatial arrangement or temporal sequence.