A direct natural consequence of drought is

A. famine and starvation

B. high mortality rate in livestock

C. drying up of most water sources

D. change in the chemical property of soils

The most common tree in the desert is the

A. date

B. acacia

C. pine

D. larch

The most obvious physical feature that distinguishes undisturbed mature soil from an immature soil is the

A. humus content

B. layered profile

C. nutrient status

D. topsoil texture

The direction of flow of ocean currents is determined mainly by the

A. rotation of the earth and land and sea breezes

B. shape of the continents and the temperature of the continental interior

C. prevailing winds and the rotation of the earth

D. depth of the ocean and the amount of fresh water inflow

The medium class of layered cloud which brings continuous rain, snow or sleet is the

A. altocumulus

B. altostratus

C. stratocumulus

D. nimbostratus

The biodiversity of an ecosystem may be reduced through the

A. extinction of plant species

B. removal of a single animal

C. introduction of a new plant

D. trapping of a single fish

A soft, black opaque carbonaceous rock that can be used to make pencils is

A. lignite

B. graphite

C. lead

D. coal

The vegetation that is characterized by tall trees climbing plants and creepers in the Amazon is called

A. pampas

B. veldt

C. selvas

D. steppes

One predominantly temperate grain that is being cultivated in some tropical areas today is

A. sorghum

B. barley

C. maize

D. wheat

The scientist who prepounded the theory of continental drift was

A. Alfred Wegener

B. William Davis

C. Arthur Holmes

D. Francis Bacon