In a gene bank,valuable plant materials are stored in a living state. $A$ gene bank is a part of which of the following?

Which of the following is not a characteristic property of chemical equilibrium?

If $x$ is real,then the minimum value of $y = \frac{x^2-x+1}{x^2+x+1}$ is

Three processes form a thermodynamic cycle as shown on the $P-V$ diagram for an ideal gas. Process $1 \to 2$ takes place at a constant temperature $(300\,K)$. Process $2 \to 3$ takes place at a constant volume. During this process,$40\,J$ of heat leaves the system. Process $3 \to 1$ is adiabatic and the temperature $T_3$ is $275\,K$. The work done by the gas during the process $3 \to 1$ is...... $J$.

When glucose reacts with bromine water,the main product is

The domestic sewage in large cities