Answer:
An egg placed in salt water will float!
Explanation:
In normal tap water, an egg will sink because it's density is greater than the density of water. But, when salt is added to the water, it's density becomes greater than the egg's density. The term used to describe this is "buoyancy."
Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

Answer:
I believe it is D.
Explanation:
Ecological succession has to do with how the habitat changes over time. So D would make the most sense.
Answer:
Fire detecting Scanner.
Explanation:
Fire detecting Scanner is a system which has the ability to scan the area and tells the changes occurs in the fire inside the earth crust. This scanner collect all information about the area on the basis of which we can take steps to avoid the damage caused by the fire. With the help of this scanner we can tell that which part is safe and which part of the area is dangerous for people.