someone who studies the buildings, graves, tools, and other objects of people who lived in the past:

(a)  

a region in space where gravity is so strong that nothing, not even light, can escape:

(a)  

(of weather, conditions in a room, or parts of the body) cold:

(a)  

needing to drink:

(a)  

the study of organisms that live in the sea or ocean, their behaviors and interactions with the environment.

(a)  

the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them:

(a)  

a computer program that makes it possible for you to read information on the internet:

(a)  

lasting for a long time or for ever:

(a)  

pieces or parts of something that continue to exist when most of it has been used, destroyed, or taken away:

(a)  

a gradual increase in world temperatures caused by gases such as carbon dioxide that are collecting in the air around the earth and stopping heat escaping into space:

(a)  

the way in which living things change and develop over millions of years:

(a)  

a person who is employed in another person's house, doing jobs such as cooking and cleaning, especially in the past:

(a)  

a person who has been trained for travelling in space:

(a)  

the scientific study of the basic characteristics of substances and the ways in which they react or combine:

(a)  

a small electronic device with a screen that allows you to read books in an electronic form:

(a)  

the set of keys on a computer or typewriter that you press in order to make it work :

(a)  

the force that attracts objects towards one another, especially the force that makes things fall to the ground:

(a)  

it is - 20 degrees C - the temperature _______ ________

(a)  

the land next to or close to the sea:

(a)