Calcium levels in the blood are regulated by
A: positive feedback mechanism.
B: negative feedback mechanism.
C: neither positive or negative feedback.
D: both positive and negative feedback.
A: positive feedback mechanism.
B: negative feedback mechanism.
C: neither positive or negative feedback.
D: both positive and negative feedback.
举一反三
- The working principle of riboswitch involves： A: negative feedback B: positive feedback C: cis-repression D: trans-activation E: feedforward
- When the mean arterial pressure fluctuates in a certain range, the stabilization of the renal blood flow belongs to A: autoregualtion B: negative feedback C: positive feedback D: feedforward
- The delivery process belongs to () A: Neuro regulation B: Humoral regulation C: Autoregulation D: Positive feedback regulation E: Negative feedback regulation
- To get a current-voltage conversion circuit, () should be introduced in the amplifier circuit. A: current-series negative feedback B: current-shunt negative feedback C: voltage-series negative feedback D: voltage-shunt negative feedback
- Basic research has: A: Positive externality B: Negative externality C: Both positive externality and negative externality D: Neither positive externality nor negative externality