Answer:
Collinear is when points are in the same straight line but coplanar is when points are all on the same plane.
The hormone that the pineal gland releases is the hormone melatonin
Answer:
Ptolemy proposed a model, he reference system is centered on the Earth
Copernicus, proposed a deferent system, this system is centered on the Sun, where it is at the origin of the system
Explanation:
Thousands of years ago, Ptolemy proposed a model to explain the movement of the planets and stars in the sky, in this model the reference system is centered on the Earth, so each body is orbiting in different spheres around the Earth as its center, this system had very complicated calculations and curves to be able to explain the orbits of the planets.
More recently Copernicus, proposed a deferent system, this system is centered on the Sun, where it is at the origin of the system, in this system the movement of the planets are ellipses, which is a much simpler explanation and has been widely accepted, in current systems the reference system is fixed in the bodies more massive, since this simplifies the explanation of the movements.
Answer:
C. The spring constant of spring 2 is larger than spring 1.
Explanation:
As we know that spring constant also called the stiffness constant of a spring is the value of force required for the deformation of the spring by a unit length.
Mathematically given as:

where:
stiffness constant
force on the spring
change in length of the spring
It is given in the question that spring 1 is easily compressible and requires less force to compress as compared to spring 2 and hence it has lesser stiffness constant than that of spring 2.