What is meant by trophic levels?

Which example describes a mutualistic relationship between organisms? young wasps prey on caterpillars. crabs eat the remains of dead fish. tapeworms feed on food in the intestines of cats ants protect a tree on which they feed.

Dna, in the nucleus carries the genetic code for making proteins in ribosomes. in the diagram, b, represents the proteins produced. dna cannot leave the nucleus to carry the genetic information to the ribosome where proteins are produced. how does the genetic code get from the nucleus to the ribosome? what does a represent? now

If 360 joules of work are needed to move and create a distance of 4 m what is the weight of the crate