Evolution Test - 27

Cretaceous period was the last and the longest segment of the mesozoic era. It lasted approx. 79 million years ago. During this time, reptiles were large in number and were dominant.
Therefore, the correct answer is option B.

Homo habilis was the first tool maker and used tools of chipped stones extensively. It is also called handy man because heaps of tools found with these fossils included sharpened stones which indicates that Homo habilis was capable of "making tools". He also led community life in caves and greatly cared for the young ones.

Cro - Magnon man emerged about 34000 years ago. Thus it is regarded as most recent ancestor of today's man. It has, therefore, been called as Homo sapien fossilis. The Cro - Magnon man was like us, about 1.8 meters tall, well - built body. Its face was perfectly orthognathous with a narrow elevated nose, broad and arched forehead, moderate brow ridges, strong jaws with man - like dentition and a well developed chin. Its cranial capacity was, however somewhat more thanours, being about 1650 cc(ours is 1400 cc). The Cro - Magnon man was the direct ancestor of the living man.

Plate tectonics is the theory that states that Earth's outer shell is divided into several plates that glide over the mantle. The plates act like a hard and rigid shell compared to Earth's mantle. This strong outer layer is called the lithosphere. Plate tectonics is the modern version of continental drift. The plates consist of two principal types of material, oceanic crust, and continental crust. The earth is considered to have 15 major tectonic plates. Seven of which are primary plates and the rest are secondary plates. The primary plates are the African plate, the Antarctic plate, the Eurasian plate, the Indo-Australian plate, the North American plate, the Pacific plate, and the South American plate. The secondary plates are the Arabian plate, the Caribbean plate, the Cocos plate, the Juan de Fuca plate, the Indian plate, the Nazca plate, the Philippine Sea plate and the Scotia plate.

In any case scientists are sure that the primordial atmosphere contained no free oxygen ($$O_2$$) and therefore ozone could not exist either. So, in primordial atmosphere, when the living organism evolved the respiration process was anaerobic, because early atmosphere contained little or no oxygen. Thus, option D is correct.
In primordial atmosphere, the respiration process was not aerobic. Thus, option B and C are wrong.
In primordial atmosphere, the respiration process was not anaerobic as it released more energy. Thus, option A is wrong.

• The gene is autosomal recessive lethal, the heterozygous individuals carrying one copy of the affected allele and one of wild type allele will serve as carriers. 
• If the genotype of homozygous individuals for the recessive lethal gene is $$qq$$ and that of homozygous individuals for wild-type gene is $$pp$$ then the genotype of heterozygous individuals will be $$pq$$. 
• According to the question, the frequency of a recessive lethal allele is (q =  0.4). Frequency of wild-type allele : $$p = 1 - q, i.e., 1 - 0.4 = 0.6$$ 
• Hardy Weinberg law states that the sum of all genotype frequencies is represented as the binomial expansion of the square of the sum of p and q. This sum is equal to one.  $$(p + q)^2$$ = $$p^2$$ + $$2pq$$ + $$q^2$$ = $$1$$.
• Hence, the frequency of carrier genotype in total population $$(2pq)$$ =  $$2$$ X $$0.6$$ X $$0.4$$ = $$0.48$$. 
• And the number of carriers in the population of 200 is = $$0.48$$ X $$200$$ = $$96$$. 

So, the correct answer is option C.

Abiogenesis of primitive polypeptides, the pro-proteins, in primitive sea was followed by formation of large spherical colloidal aggregates of proteins that remain suspended as droplets in sea water. It was driven by dehydration/opposite charge attraction. The hydrophilic amino acids attracted water molecules and led to formation of a water envelop around each aggregate. Aggregation of fat/lipid molecules formed a coating membrane around each aggregate to hold the colloidal particles together thereby facilitating chemical reactions among them. A protobiont/eobiont/protocell is defined as aggregate of abiotically produced organic molecules surrounded by non-unit membrane. Thus, the above mentioned colloidal aggregate is protobiont/eobiont/protocell. It is called so because of its role as progenitor of first life form, the prokaryotic bacteria like cell. Thus, the correct answer is option D.