Which best describes the nucleus of an atom?
a. it contains no mass.
b. it is the negatively charged part of the atom
c. it is made of neutrons and electrons.
d. it is the most massive part of the atom.

D. It is the most massive part of the atom.

Explanation:

As you know, an atom is formed by the electrosphere (where the electrons are) and the nucleus (where the neutrons and protons are).

The nucleus is a very small region in the atom and although it occupies less space than the electrosphere, it contains practically the entire atomic mass, for this reason it is the densest region of the atom. This is because the entire mass of an atom corresponds to the sum of all its protons and the protons are in the nucleus.

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !