I would guess that the answer would be :'<span>These organisms dig more shallow burrows than they used to.</span>' If the crabs actively dig burrows, as many crab species do, and a layer of oil has persisted in the lower soil strata, it makes sense that the crabs would be reducing the depths of their burrows to avoid contact with the oil. The other possibility is that the crabs might might migrate to deeper waters, but this is less likely because the crabs would be evolved to utilise the intertidal zone.
The best answer is B - the fish die.
Acid rain flows through soils. If the soil part of a watershed, aluminum is released from the soil and into the streams and lakes located in that watershed.
This lowers the pH in the lake from between 6 and 8 (which is the normal pH in lakes and streams) to less than 5.
Both increase of aluminum and lower pH are directly toxic to fish and they kill off fish populations
It is Nucleic Acids, they consist of long chains of units like the proteins, but still both are different.
I think the third one is the answer
The right answser is Chromosomes.
After DNA replication during cell cycle interphase, the chromosomes are composed of two identical chromatids attached at the centromere. Each chromatide is formed of a molecule of DNA (the nucleofilament) associated with proteins, the histones, around which it winds to form nucleosomes. At the ends of each chromatid are telomeres, consisting of repetitive DNA sequences that provide protection for chromosomal endings. Telomeres and centromere do not encode genetic information, it is non-coding DNA.
