Questions

Given two trains of length = 180 mts + 180 mts 

The distance is = Length of trains = 360 mts 

Speed = 58 - 50 = 8 kmph x 5/18 m/s

Then, Time = dis/speed = (360x18) / (8x5) = 162 sec.

Allotropes are the different physical forms of an element. Here in the given options, diamond and graphite are the pair of allotropes of carbon.

Some more examples are Molecular oxygen and ozone are pair of allotropes, Black and red phosphorous are also pairs of allotropes.

In each row, 

Sum of 1st two digit number + last two digit number = Middle two digit number

i.e., 1st row 15 + 40 = 55

2nd row 46 + 47 = 93

Similarly, 7x + 16 = 87 => x = 1.

ROM cannot be used as stack because it is not possible to write to ROM.

We know that, the nucleotide in DNA is of the form deoxyribose + phosphate group + polymerase.

Hence, Deoxyribose + Phosphate Group + Thymine is the only option in that form of nucleotide in DNA.

Heritable variation is one of the four most important factors that affect whether natural selection can occur. These factors include

1) Heritable variation

2) Descent with modification

3) Struggle for survival, and necessarily if the others are satisfied

4) Survival of the fittest.

Heritable variation allows for possibly beneficial, negative, or even neutral mutations to get filtered during each generation by natural selection--weeding out negative mutations, passing on positive and neutral ones. Without heritable variation, species would quickly fall victim to parasites who take advantage of identical genetic material in a population and evolution would not occur.

Variation is the raw material of evolution.