Which of the following statements is true related to hormones that regulate blood calcium levels? 1. Calcitonin causes bone to be broken down. 2. Calcitonin is released by the parathyroid gland to help lower blood calcium levels. 3. Parathyroid hormone is released by the parathyroid gland to help lower blood calcium levels. 4. Calcitonin is released by the thyroid gland to help lower blood calcium levels.

How do water’s relative densities as a solid and a liquid differ from that of most other substances? water’s solid and liquid forms have different densities, while most other substances have solid and liquid forms with similar densities. water’s solid and liquid forms have similar densities, while most other substances have solid and liquid forms with different densities. water’s liquid form is less dense than its solid form, while the opposite is true of most other substances. water’s solid form is less dense than its liquid form, while the opposite is true of most other substances.