Questions

The Tropic of Cancer is 23.5 degrees north latitude. It passes through 16 countries across 3 continents. They are

1. In North America,

Mexico and Bahamas(Archipelago).

2. In Africa,

Niger, Algeria, Mauritania, Egypt, Libya, Mali and Western Sahara.

3. In Asia,

Myanmar, Omen, Bangladesh, India, Saudi Arabia, China, United Arab Emirates and Taiwan.

The Tropic of Cancer also passes through 6 Water Bodies on the whole. They are

1. Indian Ocean,

2. Atlantic Ocean,

3. Pacific Ocean,

4. Taiwan Strait,

5. Red Sea (and) 

6. Gulf of Mexico.

Hence, The Tropic of cancer does not pass through Pakistan.

Bioaccumulation is defined as the increase in concentration of a substance(s) in an organism or a part of that organism.

The affected organism has a higher concentration of the substance than the concentration in the organism's surrounding environment.

For the second statement: Microorganisms eat pesticide infected things. Invertebrates eat hundreds of the microorganisms and plants infected with the pesticides, accumulating a pretty large amount of the toxin in them.

The invertebrates are generally then eaten by larger invertebrates or amphibians, which ingest hundreds of similar organisms, accumulating an even higher concentration of toxins in their bodies. Then the fish eat hundreds of these organisms, accumulating the highest concentration of toxins in themselves.

Alluvial Soils

The proportion of nitrogen is generally low, but potash, phosphoric acid and alkalis are adequate, while iron oxide and lime vary within a wide range.

Black Soils

Chemically, the black soils are rich in lime, iron, magnesia and alumina. They also contain potash. But they lack in phosphorus, nitrogen and organic matter.

Laterite Soils

With rain, lime and silica are leached away, and soils rich in iron oxide and aluminium compound are left behind.