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_______1. A relic, remnant, or representation of an organism that
existed in a past geological age, or of the activity of such an organism,
occurring in the form of mineralized bones, shells, etc.
_______2. The third planet from the sun, the only planet on

which life is known to exist.
_______3. The force of attraction that moves or tends to move
bodies towards the centre of a celestial body, such as the earth or

moon.
________4. The great circle of the Earth with a latitude of 0°,
lying equidistant from the poles; dividing the Northern and Southern
hemispheres.

________5. A geometric surface, symmetrical about the three
coordinate axes, whose plane sections are ellipses or circles.
________6. A closed conic section shaped like a flattened circle

and formed by an inclined plane that does not cut the base of the cone.
________7. A hypothetical surface that corresponds to the mean
sea level and extends at the same level under the continents.

III. GRAMMAR REVIEW

Task 1 Define whether the sentences are used in Active or
Passive Voice. Transform those in Active Voice into Passive
Voice. Name the tense form used.

1. The history of the Earth has been always the centre of interest
for many philosophers and discoverers.
2. Gradually, dust particles were attracted to each other and came
together to form a huge spinning disk.

3. Dense material sank to the center, while the lighter pieces
created the crust.
4. It is now known that the Earth turns on its axis.

5. Scientists define the Geoid as the theoretical shape of the Earth.
6. The geoid represents the Earth gravity field in a graphical

form.
7. We know ellipsoid as a smooth elliptical model of the Earth’s

surface.

8. The reference surface for horizontal coordinates requires a
mathematical definition and description.

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