One of the parents of a child has phenylketonuria (PKU), which is caused by recessive alleles. The other parent does not have the PKU alleles. What is the chance that the couple will have a child with phenylketonuria?
A 0%
B 50%
C 75%
D 100%
Which disease most likely occurs after excessive exposure to ultraviolet radiation?
A malaria
B asthma
C skin cancer
D polio
Why are humans inportant to the life cycle of malaria parasites?
A Malaria parasites kill humans.
B Malaria parasites only live in human cells.
C Malaria parasites can live in mutual symbiosis with humans.
D Malaria parasites use humans for reproductive purposes.
In an experiment, Pavlov caused a dog to salivate when it heard the ring of a bell. Which type of learning was demonstrated by the dog?
A habituation
B imprinting
C conditioning
D trial and error
If the xylem in a young tree is damaged, which process is first affected?
A performing photosynthesis
B transporting sugar to the roots
C transporting water to the leaves
D absorbing water from the soil
A plant species lives in an area with limited sunlight. Which physical adaptation would be most useful to the plant?
A colorful flowers
B large leaves
C deep roots
D thin cuticle
The crab Lybia tessellata carries a pair of sea anemones on its claws. The crab uses the sea anemone’s stinging tentacles as protection and the sea anemone obtains small food particles released by the crab as it feeds. Which type of symbiotic relationship does this best illustrate?
A commensalism
B mutualism
C parasitism
D predation
Which substance is considered to be a factor affecting Earth’s ozone layer?
A chlorofluorocarbons
B ethyl alcohol
C nitrogen gas
D water vapor
Which is a use of genetically engineered bacteria?
A identifying the remains of an unknown person
B developing a DNA fingerprint for blood left at a crime scene
C making human insulin for diabetics
D producing corn that is resistant to herbicides
Which types of organisms developed first due to the early environmental conditions on Earth?