Halite is transparent, but it can be died many different colors calcite is a white or colorless mineral consisting of calcium carbonate. It is a major constituent of sedimentary rocks such as limestone, marble, and chalk, can occur in crystalline form gypsum is a soft white or gray mineral consisting of hydrated calcium sulfate.
Answer:
The correct option is: A) As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight.
Explanation:
Seasons on Earth are the changes in the weather caused due to the <u>titled axis of the Earth, relative to the orbital or ecliptic plane</u>, while orbiting around the Sun. The Earth's axis of rotation is<u> tilted approximately by an angle of 23.4°. </u>
This results in the change in the intensity of the sunlight received by the Earth's surface, due to which the southern and the northern hemispheres <u>experience opposite seasons.</u>
<h2>
Answer: B)Scientists’ understanding of cells continually improved as the results of studies built upon each other over time and formed the cell theory.</h2>
Explanation:
Nowadays we know <u>cells are essential microscopic units that make up the living beings, capable of reproducing independently. </u>
However, this is the result of a long process of discoveries and studies made since the 19th century, in which the continuous improvement of new technologies was helpful.
In fact, it is wel known the English scientist Robert Hooke was the first to discover the existence of cells by looking through a compound microscope at a cork sheet, realizing that it was made up of small polygonal holes (like those of a honeycomb) that reminded him of the chambers in which the monks stayed (called cells). Then, during the next centuries more studies were made until we had the current knowledge about the structure of a cell.
