The pneumatic bones are important to birds for respiration. They are hollow bones which are connected to the bird's respiratory system and are important for birds to be able to breath. Examples of pneumatic bones are the skull, humerus, clavicle, keel (sternum), pelvic girdle, and the lumbar and sacral vertebrae.
One of the most abiotic factor that may affect humans directly is waster availability because with out water we can get dehydrated and die.
Asteroids vary greatly in size and are mostly made up of frozen water and gas. This one is true.
They are said to be "mostly formed of ice and gas" as they rarely can be found consisting of stone, nickel and iron. These are extremely dangerous in our Universe.
If there's options, I assume mutation?
Answer:
Function of each male reproductive system-
They produce, maintain and transport sperm and semen . They discharge sperm into the female reproductive tract. They produce and secrete male sex hormones.
Function of each female reproductive system-
The ovaries produce the egg cells, called the ova or oocytes. The oocytes are then transported to the fallopian tube where fertilization by a sperm may occur.
