A flower which can be divided into two equal halves by only one plane is
zygomorphic
actinomorphic
regular
perfect
A.
zygomorphic
A flower is said to be zygomorphic, when they are bilaterally symmetrical, ie, can be bisected into two halves. Eg. Dolichos lablab etc.
A flower is said to be actinomorphic, when it is radially symmetrical and is capable of division by any longitudinal plane into equal halves. Eg, Tulip flower.
Calcium level decreases in the blood due to hyposecretion of
parathyroid hormone
calcitonin
thyroxine
adrenaline