When its traveling down the fallopian tube in this process it starts to divides to form a ball of cells called a blastocyst . hope this helps you :)
<span>The lungs are the respiratory structure that controls breathing. They make up a substantial part of the respiratory system, along with the trachea, the ribs, the intercostal muscles and the diaphragm. Each lung contains small tubes called bronchioles which end in air sacs called alveoli.</span>
Opportunistic infections (OIs) are infections that occur more frequently and are more severe in individuals with weakened immune systems, including people with HIV. People are at greatest risk for OIs when their CD4 count falls below 200, but you can get some OIs when your CD4 count is below 500.
