Which of the following expressions is not correct (不正确)? A: If a system is only acted by conservative forces （保守力）, the mechanical energy（机械能）must be conserved （守恒）. B: If net external force is zero then the linear momentum of the system must be conserved. C: If net external force is zero, then the mechanical energy of a system must be conserved. D: If net external force is zero, then the mechanical energy of a system may not be conserved.

There is a growing ________ among ecologists and resource management specialists that biodiversity cannot be adequately conserved by protected areas alone.

‍下列（）可以用于预测蛋白质保守结构域。‍ A: prosite B: NCBI Conserved Domains C: SMART D: PredictProtein

下列（）可以用于预测蛋白质保守结构域。 A: prosite B: NCBI Conserved Domains C: SMART D: PredictProtein

The structures of many proteins—and their constituent domains—are so stable and effective that they have been conserved throughout evolution among many diverse organisms.

Even though I'm quite a （）person, I like meeting people. A: preserved B: conserved C: deserved D: reserved

San Diego Wild Animal Park is the best kind of 'zoo' and a sanctuary for 41 ____________ species. A: beautiful B: various C: conserved D: endangered

Which of the following is not a feature of CRISPR? A: Contain palindromic DNA repeats B: Have highly conserved spacer regions C: Provide adaptive immunity to Bacteria and Archaea D: Used as a molecular biology tool for genome editing

Two masses collide and stick together. Before the collision one of the masses was at rest. Is there a situation in which the kinetic energy is conserved in such a collision? A: Yes, if the less massive particle is the one initially at rest. B: Yes, if the more massive particle is the one initially at rest. C: Yes, if the two particles have the same mass. D: No, kinetic energy is always lost is such a collision.