4. Elephants appear in the fossil record after dinosaurs became extinct.
The relative dating is a technique of dating with respect to any past event. In this case, two events are discussed to be occurred in a sequence related to one-another. In the option 1, the amphibians are said to be evolved before reptiles. So, the evolution of the amphibians is relatively dated with the evolution of reptiles. Same in the option 4, the evolution of the elephants is relatively dated with the extinction of the dinosaurs.
Answer: 1. Amphibians evolved before land reptiles.
4. Elephants appear in the fossil record after dinosaurs became extinct.
Relative dating is an aging method which describes past events, that determines the age of an object or organism by comparing it with other object or organism. Therefore, it can give relative age but not absolute age of the object or organisms. Relative age can be determined by the identifying the strata of rock layers in which fossils are found. More deeper the strata more primitive will be the living organism. Therefore, amphibians evolved before land reptiles and elephants appear in the fossil record after dinosaurs became extinct depends upon relative aging for estimation of age.
The number of chromosomes in a sex cell is half the number of chromosomes in a body cell. Think of it this way: 1 egg (women sex cell) combine with 1 sperm (male sex cell) to make 1 whole cell.
