The four important characteristics of respiratory surface are:
1. Thin walls
2. Moisture
3. Large surface area
4. Blood supply
Respiratory system or respiratory tract is divided into upper and lower tract. Upper respiratory tract includes nose and its cavities, sinuses, pharynx and the part of the larynx. Lower respiratory tract consists of the trachea, bronchi, bronchioles and the alveoli.
Alveoli are the ends of the respiratory tract the smallest units in it. Alveoli are small folded air sacs that are branching off from alveolar ducts and providing an extremely large surface area for the gas exchange. Gas exchange occurs thanks to small blood vessels – capillaries that surround alveoli and it occurs via the process of diffusion.
So, respiratory surface is thin membrane also known as the blood–air barrier that consists of the alveolar epithelial cells, their basement membranes and the endothelial cells of the alveolar capillaries.
Answer:
D
Explanation:
DNA use thymine and rna uses uracil but they use a,c,g together
Answer:Bisexual flowers are complete flowers, containing both androecium and gynoecium in one flower. Therefore, bisexual flowers contain both stamens and pistils in the same flower. Hence, bisexual flowers are called hermaphrodite or androgynous flowers as well.
Explanation:
Because you cannot test it or observe it.
A scientific theory are created through the scientific method, in the scientific method you need to be able observe it and experiment.
Follicle stimulating hormone (FSH) and Luteinizing hormone (LH) are Gonadotropins stimulated in the gonads. In females, they are located in the ovaries. They are not needed for life yet important for reproduction. Progesterone which is being secreted in corpus luteum is needed for maintenance of pregnancy thus if a female has a low FSH and LH it will affect the chance of her be pregnant.