Hi!
The selection in this case would be natural selection.
Natural selection is a process that involves organisms with favorable characteristics having a higher chance of reproductive success, and passing on their traits onto the offspring. This process, as opposed to artificial selection, does not involve human intervention and is a natural phenomenon.
In our case, whales with maximum length (the favorable trait) are mating on accord of their own, without external factors governing the process; hence, the selection is natural.
Hope it helps!
The question is incomplete. The complete question is:
Question: Innate immunity:
a) is based on recognition of antigens that are specific to a pathogen.
b) is the first and most general, mechanism of protection against pathogens
c) is found only in vertebrates
d) depends on an infected animal's previous exposure to a pathogen
Answer:
b) is the first and most general, mechanism of protection against pathogens
Explanation:
Innate immunity is the nonspecific immune response that provides immediate and the most general protection against all types of pathogens, parasites, toxins and cancer cells. Innate immune responses serve to prevent the pathogens from entering the body. The components of innate immunity also rapidly destroy those pathogens that have entered the body.
Some of the components of innate immunity are the first line of defense such as the physical and chemical barriers of the skin and mucous membranes. The components of the second line of defense such as natural killer cells, phagocytes and inflammatory response are also involved in innate immune responses.
For example, cuticle or skin serves as a physical barrier to pathogens that come in contact with an animal’s body. Phagocytosis kills the bacteria that invade the body.
It would be c. More co2 means more radiation from the sun.
The correct answer is absolute threshold.
Absolute threshold is a neurobiological term referring to the lowest level of a stimulus that a person is able to detect. The stimulus can either be touch, sound, taste or light.
Regarding taste, the absolute threshold of taste is the lowest concentration of a certain compound which can be detected by the human sense of taste.
