What comprises two-thirds of botswana's land?
a. the mitumba mountains
b. the okavango delta
c. the kalahari desert
d. victoria falls

C. The Kalahari Desert

Explanation:

Botswana is a country located in the southern parts of Africa . The country is a landlocked region as they lack access to the oceans. Botswana shares boundaries with Namibia, South Africa , Zambia and Zimbabwe.  

The Kalahari desert is a desert located in the southern part of Africa and the landscape covers three countries namely Namibia,Botswana and south Africa.

The Kalahari desert  occupies roughly 70 percents of Botswana's land mass . In other words it occupies two-third of  the Botswana's land . The Kalahari desert is a semi arid desert with limited amount of rainfall.

The picture above shows you how Kalahari deserts looks like.  

Magma forms by partial melting of upper mantle and crust. partial melt means that only a fraction of the available material forms a melt, and that the remainder stays solid. the partial melt rises because of its lower density and ascends through he crust. this is so conclusive mean the answer would be magma igneous rocks or balistic magma.

The correct answer is:   [b]:   "physical systems" .