Materialized class slogan

1. For the whole system, mechanical energy is conserved, but not just the ball. For the ball, there is an external force (elasticity) doing work for him, so the mechanical energy is not conserved, but for the whole system, there is no energy loss, so the mechanical energy is conserved.

2. For example, HCL in the molten state is not conductive in the molten state, because compounds with valence of * * * will not ionize in the molten state. The definition of electrolyte is yes or no, that is to say, it is enough to meet one condition. Some substances will decompose in the molten state. Electrolyte refers to a compound that can be melted in an aqueous solution or can conduct electricity in a molten state, not necessarily in a molten state.

I haven't studied biology for a long time. I really don't know. I suggest you throw away mitosis Baidu Encyclopedia. The replication of DNA and the synthesis of protein should be that pollen is a germ cell only in the interphase, and it can develop into an individual in pollen culture in vitro (colchicine treatment), which can reflect the totipotency of cells.

4. Of course, it embodies omnipotence. Remember, as long as cells are cultured into plants, it embodies the totipotency of cells, because it must go through the process of plant tissue culture.

I hope to adopt.