A Why is it useful for crabs that live on the seashore to have both lungs and gills.
b If equal volumes of blood go through the lungs and gills of light-blue
soldier crabs suggest the mean percentage of oxygen that would be found in
the blood has gone through only the gills. Explain your reasoning.
c What does this tell you about how efficient both lungs and gills are in these
crabs?
d Suggest three reasons for this difference.

Hormones are chemical molecules produced by endocrine glands. one such endocrine gland is the thyroid gland, which synthesizes the thyroid hormone, which in turn affects the heart muscles. which two statements describe the probable reason for the function of the hormone? the cells in the heart have specific receptors that allow for the intake of hormones. the heart and the endocrine glands have the exact same types of cells. all cells make the same types of hormones. thyroid hormones show their effect on the heart by means of specialized cells. thyroid cells and cardiac cells have different dna.