An example of human activity that has had a positive effect on the environment is the: *
a. Disruption of natural habitats through deforestation
b. Capture and sale of rare South American birds
c. Use of reforestation to control erosion in the mountains
d. Hunting of endangered species of animals

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.

Due tonight 10 points will mark brain

Which enzyme is responsible for “unzipping" the dna by breaking the hydrogen bonds between the nucleotides?