The early stage human embryo distinctly possesses

• gills

• gill slits

• external ear (pinna)

• eye brows

The phase of menstrual cycle in humans that last for 7 - 8 days, is: 

• follicular phase

• ovulatory phase

• luteal phase

• menstruation

Pollen grains are able to withstand extremes of temperature and dessication because their exine is composed of

• cutin

• suberin

• sporopollenin

• callose

One of the genes present exclusively on the X-chromosome in humans is concerned with

• baldness

• red-green colour blindness

• facial hair/moustaches in males

• night blindness

Which one of the following statements with regard to embryonic development in humans is correct?

• Cleavage divisions bring about considerable increase in the mass of protoplasm

• In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second

• With more cleavage divisions, the resultant blastomeres become larger and large

• Cleavage division results in a hollow ball of cells called morula

Assertion : Mast cells in the human body release excessive amounts of inflammatory chemicals which cause allergic reactions.

Reason : Allergens in the environment on reaching human body stimulate mast cells in certain individuals.

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements

Assertion : Use of fertilizers greatly enhances crop productivity.

Reason : Irrigation is very important in increasing crop productivity.

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements

Assertion : Bats and whales are classified as mammals.

Reason : Bats and whales have four-chambered heart.

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements

49.

Assertion : Organochlorine pesticides are organic compounds that have been chlorinated.

Reason : Fenitrothion is one of the organochlorine pesticides. 

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements

Assertion : Holoblastic cleavage with almost equal-sized blastomeres is a characteristic of placental animals.

Reason : Eggs of most mammals, including humans, are of centrolecithal type.

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements