Answer:
The mass number of an atom is its total number of protons and neutrons. Atoms of different elements usually have different mass numbers , but they can be the same. For example, the mass number of argon atoms and calcium atoms can both be 40.
Explanation:
D) The Earth was hit by a one or more objects from space 65 million years ago. The iridium layer shows an extraterrestrial cause for the extinction at the Cretaceous Tertiary boundary, discovered by the Alvarez family. The first discovery of this layer was in the Bavarian alps, in Lattengebirge. The Alverez family proposed that the extinction of the dinosaurs was due to a large meteor hitting the Earth at the end of the Cretaceous period, marking the KT boundary with this clay layer which has a high content of iridium. Iridium is not common on Earth, but is common in meteors.
<u>Answer:</u>
Charles Darwin’s study of evolution predicts that genetic evidence would show that all organisms share a common ancestor.
Option: (B)
<u>Explanation:
</u>
- Through his "theory of evolution", Darwin found that the species exist and new species form based on natural selection.
- He studied the animals and birds in Galapagos island for his evolution theory.
<u>The four key points of Darwin's Theory of Evolution:</u>
- individuals of any species are not identical;
- genes are passed from one 'generation' to another;
- more offspring are born than can survive;
- only the 'survivors of the competition' for the resources will reproduce.
Sterilization is the process that kills all microbes by the use of physical/chemical agents.
