A stand of Douglas fir trees is home to 3 similar species of small insect-eating birds. They eat a variety of insect species: one insect burrows into the tree bark, one lives in the tree needles (leaves), and one flies between trees. All three bird species are able to eat any of the insect species.
If one bird species eats only insects in the tree bark, another forages only in the needles, and the third only catches insects as they fly between trees, then the birds are experiencing:

A. resource partitioning.
B. character displacement.
C. mimicry.
D. predation.
E. intraspecific competition.

A. resource partitioning.

Explanation:

Resource partitioning refers to as the division of limited food or resources by organisms in order to prevent competition in an environment. In situations where there are limited resources or food available to organism s in an ecological niche, such organism in that niche will need too develop strategic ways to coexist and to prevent competition, so that the resources can be shared across.

The birds illustrated in the question above are therefore experiencing resource partitioning.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

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