Mutation are two types somatic and germ cell mutation...as there is mutation in germ cell it will alter the normal behavior and produce variation !
random fertilization also causes variation as different setup of genes meets with another different...so chances of variation increases !
and third crossing over is in meiosis when chiasmata forms....so in this two homologous chromosome attach to each other and on separation ... some part exchange so leads to variation !
Pituitary gland is the master gland
Answer:
d. malleus > incus > stapes > oval window
Explanation:
Sound waves enter external auditory canal which makes the eardrum to vibrate. Malleus is in contact with eardrum while stapes is in contact with the oval window. Movement of malleus makes the incus to move which in turn stimulates large movement in stapes.
Since stapes is in contact with the oval window, the vibration from stapes passes to the oval window. Hence, among the given options, the correct order of movement of sound waves is "malleus > incus > stapes > oval window"
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They would fall in the clumped or even category