Question 1

Which one of the following statements is totally wrong about the occurrence of notochord, while the other three are correct?

Accepted Answer

It is absent throughout life in humans from the very beginning

Question 2

Which one of the following statements is totally wrong about the occurrence of notochord, while the other three are correct?

Accepted Answer

It is absent throughout life in humans from the very beginning

Question 3

Selaginella and Salvinia are considered to represent a significant step towards evolution of seed habit because

Accepted Answer

embryo develops in female gametophyte which is retained on parent sporophyte

Question 4

Which one of the following is a correct statements?

Accepted Answer

Pteridophytes like selaginella and Salvinia are heterosporous as they produce two kinds of spores micro (small) spores and macro (large) spores, which germinate and give rise to male and female gametophyte respectively. The female gametophyte in these plants are retained on the parent sporophytes for variable periods. The development of the zygotes into young embryos takes place within the female gametophyte. This event is the precursor to the seed habit, considered to an important step in evolution.

Question 5

Which one of the following shows isogamy with non-flagellated gametes ?

Accepted Answer

In spirogyra, non-motile gametes are present, both of the gamete are morphologically same.

Question 6

Male gametophyte with least number of cells is present in -

Accepted Answer

Most reduced male gametophyte or minimum no. of cell in male gametophyte is present in angiosperm (3 celled male gametophyte). Lilium is angiosperm.

Question 7

In which of the following gametophyte is not independent free living?

Accepted Answer

Gametophyte is dependent in gymnosperms and angiosperms whereas independent in bryophytes and pteridophytes.Bryophytes - Funaria, MarchantiaPteridophytes - PterisGymnosperm - Pinus

Question 8

Why are living organisms classified?

Accepted Answer

(i) Classification makes the study of living organisms convenient.
(ii) It helps in specific identification of various living beings.
iii) It informs about the evolutionary relationship by establishing the gradually increasing complexity of form and structure in different groups of plants and animals.

Question 9

In angiosperms, the oospore on development produces

Accepted Answer

[B] Embryogeny is the development of mature embryo from zygote or oospore.

Question 10

In majority of angiosperms -

Accepted Answer

[C] Meiosis occur in spore mother cells in angiosperms.

Question 11

The ovary is half inferior in :

Accepted Answer

[C] Plum

Question 12

The ovary is half inferior in :

Accepted Answer

[C] Plum

Question 13

Egg apparatus of angiosperm consists of

Accepted Answer

[A] Egg apparatus of angiosperm is 3 celled. It has one egg cell and two synergids on either side of egg cell. 3 antiipodal are present on chalazal side. The secondary nucleus is binucleate is present in the centre of embryo sac.

Question 14

Probiotics are

Accepted Answer

Probiotics are defined as live microorganisms, including Lactobacillus species, Bifidobacterium species and yeasts, that may beneficially affect the host upon ingestion by improving the balance of the intestinal microflora. The dietary use of live microorganisms has a long history.

Question 15

Smallest cellular organisms are

Accepted Answer

Smallest cellular organisms are mycoplasma which are smaller than smallest bacteria but larger than largest viruses. They develop prokaryotic cells but lack cell wall, thus representing a naked piece of propoplast bounded by plasma membrane.

Question 16

Aflatoxin is produced by :

Accepted Answer

Aflatoxin in a fungal toxin synthesized by fungi like Aspergillus flavus, Aspergillus fumigatus, etc., while storage of seeds and cereals and it causes severe damage to poultry. Toxic level is so high to cause death of birds consuming such a contaminated food.

Question 17

F-factor of plasmid DNA provides :

Accepted Answer

F-factor occurs on plasmids of bacteria and it induces fertility in bacterial cells, F positive cells are considered male or donor cells and the F-negative cells are female or recipient cells. F-factor may occur integrated with bacterial genome and then such cells are called highly fertile HFR (High Frequency of Recombination) variety.

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Solutions for Biology-for-NEET-Volume-2-Class-XII by Career Point, Biological Classification

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