What does the term 'reproductive isolation' refers to?

(1) An individual is unable to fertilise itself 

(2) Genes are not exchanged between two populations

(3) Individuals from two populations never mate

(4) Individuals form two populations never produce offsprings

Below are listed some pairs of characters. the homologous pair is

(1) forelimbs of dog and camel

(2) insect wing and batwing

(3) feathers of birds and fins of fish

(4) lens of vertebrate and arthropod

Pythons possess tiny leg bones that serve no purpose in locomotion. Such organs are

(1) homologous organs

(2) analogous organs

(3) vestigial organs

(4) Both (a) and (c)

The two critical steps in the evolution of humans were the

(1) evolution of bipedalism and the enlargement of the brain

(2) making and using tools

(3) using fire and making shelters

(4) exhibiting culture and having sophisticated tools

Why does it is said that looking at stars on a clear night sky means looking back in time?
A. What we are seeing at that time is actually has stated its journey millions of years back
B. What we are seeing at that time is actually has stated its journey trillions of days back
C. What we are seeing at that time is actually has stated its journey thousands of days back
D. What we are seeing at that time is actually has stated its journey thousands of kilometers away

Which of the following statements are not true?

Big Bang theory attempts to explain

Which of the following is not true about Big Bang theory?

Which of the following is true regarding early earth?

1. Earth was supposed to have been formed about 4.5 billion years back.

2. The atmosphere of early earth was full of water vapour.

3. The surface of earth was covered by water vapour, methane and carbondioxide, the three compounds, formed from molten mass.

4. The UV rays from the sun broke up water into hydrogen and oxygen and lighter oxygen escaped.

…….combined with ….. and….. to form water, CO2 and others.