Anew hormone is discovered. analysis suggests that it is synthesized on demand and has a long half-life in the bloodstream. it seems to activate gene transcription in its target cells, though no cell surface receptors can be identified. which type of hormone is this most likely to be?

The correct answer is - a steroid hormone.

Explanation:

Steroid hormones are the hormones that are derived from the cholesterol and are non-polar or lipid-soluble molecules. These hormones are helpful to maintain or regulate many biological processes by modulating gene expression.

The steroid hormone can go through the cell membrane and bind to the receptor present in the cytoplasm of the particular target site which further moves to another receptor in the nucleus and bind there activate gene transcription.

Thus, the correct answer is - a steroid hormone.

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