Answer:
Acid rain refers to the rain which acidic in nature having a form of precipitation and elevated levels of hydrogen ions (low pH). The normal pH of rain is around 5.6
Rising concentration of Sulfur dioxide (SO2) and nitrogen oxides (NOx) in atmosphere is one of the cause of acid rain. Sulfur dioxide (SO2) and nitrogen oxides (NOx) are released by vehicles, fossil-fuel power plants and oil refineries.
When a sulfur dioxide and nitrogen oxides released in air they mix with oxygen, water and other chemicals in the air and form sulfuric and nitric acids. sulfuric and nitric acids mix with precipitation and its pH level is about 5.2 or below.
Hence, rising concentration of SO2 And NO2x is one of the biggest reason of acid which damages agriculture, buildings and wildlife et-cetra.
B. some species die out when environmental changes occur
Answer:
Option D is a correct answer
Explanation:
An adaptation is adapted to suit the environment as every environment is different.
Different environment aids to different kind of adaptations that perfectly suits the animals living there.
The adaptation of an animal living in the desert region will have adaption to work in hot climate. The plant that grows in a desert area have no leaves and broad stem to store water.
The animals that live in the polar regions have thick fur to provide insulation and heat to live in polar region.
Answer: After 3 rounds, 8 segments having 2 original strands on different segments will be present.
Explanation:
The polymerase chain reaction selectively and repeatedly copy the double stranded DNA (dsDNA) in the PCR machine.
1st round:
Single piece of double stranded DNA (dsDNA) unwinds in two seperate strands, before complementary nucleotides are synthesized to establish double helix.
2nd round:
The two dsDNA yields 4 segments before complementary nucleotides are synthesized
3rd round:
The four dsDNA yields 8 segments before complementary nucleotides are synthesized.
Therefore, at the end of 3 rounds, the two original strands will be present on the 8 different segments of copied DNA.
