Questions

A substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means.

Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen.

Material composed of only one kind of matter throughout (same atoms or same molecules).

Desertification is a type of land degradation in which a relatively dry area of land becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife.

Conversion of a grassland or an already arid land into a desert through indiscriminate human actions magnified by droughts.

Hence, forest improving to deserts is refers to desertification.

Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all. The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus.

Adding the corresponding numbers in first and last figures gives the corresponding number in the middle figure.

i.e, 4 + 3 = 7

13 + 2 = 15

2 + 4 = 6

9 + 1 = 10

Chihuahua