Joy and sorrow are the two most closely related emotions. They are on the same continuum. The best example is when you feel extremely joyous, you cry. You will also cry when you feel sorrow.
Humans and chimpanzees are the two species that are most closely related to each other.
Humans and chimpanzees are the two species that are most closely related in terms of genetic similarity.
Family and kingdom
Clasifiaction
Love and hate are so closely connected because they are the two most strongest emotions they are easily seen and expressed
Menicius and Lao-zi
Canis familiaris (domestic dog) is most closely related to Canis lupus (wolf).
All species of bacteria (and several other organisms) reproduce by cloning, so two unmutated bacteria of the same species have identical DNA, and are as closely related as it is possible to be. This is true for all clones.
Empathy is the ability for a person to feel someone else's emotions. It is closely related to sympathy, and the two words share the same Greek root pathos. As a superpower, it refers to the ability to sense the emotions of others and control them at will.
DNA sequence similarity is the most useful factor in determining whether two organisms are related. The more similar the DNA sequences of two organisms are, the more closely related they are likely to be evolutionarily.
To determine which two organisms are most closely related in figure 18-4, one would typically look for the organisms that share the most recent common ancestor on the phylogenetic tree presented. The organisms that branch off from the same node or point in the tree are considered to be more closely related to each other. If you can provide the specific organisms listed in the figure, I could give a more tailored answer.
If you mean are most closely related to dinosaurs sharks and crocodiles closest alive today.