Question: Hazards to aircraft include debris, nesting birds, and reduced friction levels due to environmental conditions such as ice, snow, or rain. Part of runway maintenance is airfield rubber removal which helps maintain friction levels. The fields must be kept clear of debris using cleaning equipment so that loose material does not become a projectile and enter an engine duct (see foreign object damage). In adverse weather conditions, ice and snow clearing equipment can be used to improve traction on the landing strip. For waiting aircraft, equipment is used to spray special deicing fluids on the wings.
Is there an answer to this question: Why must the field be kept clear of nesting birds?

Answer: unanswerable

Question: Although the elements usually must be soluble in the liquid state, they may not always be soluble in the solid state. If the metals remain soluble when solid, the alloy forms a solid solution, becoming a homogeneous structure consisting of identical crystals, called a phase. If the mixture cools and the constituents become insoluble, they may separate to form two or more different types of crystals, creating a heterogeneous microstructure of different phases. However, in other alloys, the insoluble elements may not separate until after crystallization occurs. These alloys are called intermetallic alloys because, if cooled very quickly, they first crystallize as a homogeneous phase, but they are supersaturated with the secondary constituents. As time passes, the atoms of these supersaturated alloys separate within the crystals, forming intermetallic phases that serve to reinforce the crystals internally.
Is there an answer to this question: What are alloys called when the soluble elements separate after crystallization occurs?

Answer: unanswerable

Question: Plymouth also has 71 state primary phase schools, 13 state secondary schools, eight special schools and three selective state grammar schools, Devonport High School for Girls, Devonport High School for Boys and Plymouth High School for Girls. There is also an independent school Plymouth College.
Is there an answer to this question: How many state grammar schools are based in Plymouth?

Answer: three

Question: Classification of predators by the extent to which they feed on and interact with their prey is one way ecologists may wish to categorize the different types of predation. Instead of focusing on what they eat, this system classifies predators by the way in which they eat, and the general nature of the interaction between predator and prey species. Two factors are considered here: How close the predator and prey are (in the latter two cases the term prey may be replaced with host) and whether or not the prey are directly murdered by the predator is considered, with true predation and parasitoidism involving certain death.
Is there an answer to this question: Who is involved in classifying different types of prey?

Answer:
unanswerable