Which step in the formation of calcitriol is regulated by the parathyroid hormone

The word that would fill this space would be calcium. Calcitonin lowers it, calcitriol increases it, and parathyroid hormones balance it out.

I hope this helped you! Good luck. :)

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)

hey bro i looked it up on google the structure of the eye-spot in euglena viridie, e. ehrenbergii, and phacus pyriyorme is not as franzé haa described it. the so-called “crystal body” and “lens bodies” were not found in any of the individuals of the species examined by me. as earlier observers have stated, the eye-spot consists simply of a mass of pigment granules arranged in a single layer, and probably embedded in a protoplasmic framework, but the latter could not be seen, and its presence was only inferred from the fact that the pigment granules must be held together in some way, thd the eye-spot as a whole is capable of expansion, and that the pigment granules can be separated from each other.

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