What defines radial symmetry?
a) Any plane of symmetry passing through the center of the organism splits it into equal halves.
b) Only five planes of symmetry passing through the center of the organism splits it into equal halves.
c) Only one plane of symmetry splits the organism into equal halves.
d) No planes of symmetry exist; the organism cannot be split into equal halves.

A

Explanation:

symmetry about a central axis, as in a starfish or a tulip flower

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.