Answer:
B
Explanation:
Semi-arid climates are dry and desert like climates, considering the others aren’t really desert climates the Arabian peninsula mainly consist of deserts.
hope this helps!
A net population decline resulting from an "excess of deaths over births".
Option: A
<u>Explanation</u>:
Demographic transition is a shift from higher to lower level of fertility and mortality.Rapid development in industrialization and urbanization in 
century resulted into enormous population growth. But decline in early 
century covered many reasons like consequences of two calamitous wars, where Europe suffered large population declination due to battle death and civilian causalities in World War I and II. Hence the acceleration of population growth in 19th century but downfall in 20th is also considered as balance.
B since there is a high chance of birth and a low chance of death
What do you mean by the earths spheres
