Bronze age (3000 to 1100 BCE)-

Iron age (1100 to 30 BCE)

Introduced or Foreign or non-native species Introduced species occur in an area where they are not native but were brought there through human influence — either purposefully or accidentally.

4. Prevailing Winds: Prevailing winds bring air from one type of climate to another. For example, warm winds that travel over water tend to collect moisture as they travel; the water vapor in the air will condense as it moves into colder climates, which is why temperate coastal areas often receive heavy rainfall.

5. Landmass:

The Sahara Desert-arid desert

The Atacama in Chile-coastal desert

The Antarctic is an example of a cold desert.

Semi-arid deserts are found in North America, Greenland, Europe, and Asia.

Arid deserts are hot and dry, with very little vegetation. Arid gets so little or no rain. They are hot during the day and cold at night. Animals burrow at day and come out at night. Sahara desert. Great Basin desert
Semi-arid deserts are arid deserts, but they somewhat still receive rain.
Cold Deserts change with the seasons, hot in summer but snow in winter. Cold deserts are found in the Antarctic, Greenland, Iran, Turkestan, Northern and Western China.
Coastal Deserts: As the name implies, coastal deserts are deserts stretching along the sea coast. They are one of the four major types of deserts. Their nearness to the sea gives them unique properties not found in deserts elsewhere. Such deserts are usually found on the western edges of continents with cold ocean currents running parallel to the coast. As the cold currents cool the air above, the air is unable to hold moisture and most of it falls as rain on the sea before it reaches land. Thus, the land alongside the coast with cold ocean currents receives little or no precipitation and turns into a desert.

Oasis??
Oasis is a part of a hot (arid) desert. Oasis is a pool of water found in ze desert, it pops up in spring and is a place where plants grow, animals come to drink water, find shade and more.

While temperatures are often extreme in some grasslands, the average temperatures are about -20°C to 30°C. Tropical grasslands have dry and wet seasons that remain warm all the time. Temperate grasslands have cold winters and warm summers with some rain.

Grasslands are found in Africa, North America, Central Asia, South America, and near the coasts of Australia. The largest grasslands are in East Africa.

Two main types of grasslands are Temperate and Tropical.
Tropical: They are sometimes called "savannas",   found in parts of Africa, the soil is thin, animals like lions and giraffes live here. Hot all year round.
Temperate: Mostly grass, few trees, and shrubs receive more rain than tropical grasslands. Prairies are part of these. Hot summers and cold winters. There is rain but not too much rain. Rain can support trees and shrubs.

Characteristics:

Dry- Scanty rainfall due to low evaporation.

Permafrost-Below the topsoil, the ground is permanently frozen year-round. 

Barren-The tundra has few nutrients to support plant and animal life.
A little amount of Precipitation

Separated: Alpine and Arctic:
Alpine is located on rocky mountain tops, similar to Arctic Tundra in terms of temperature and precipitation. 
Arctic Tundra is located in the northern hemisphere.

Low shrubs, mosses, grasses, lichens, and some flowers. 
Icy Rivers
polar bears, foxes, Wolves, some birds, Squirrels..
Global Warming, Oil, Hunting are some threats. 
Oils and minerals are in solid which is risky.