47. Droughts and the melting of the polar ice caps can occur when carbon dioxide

Question

47. Droughts and the melting of the polar ice caps can occur when carbon dioxide levels double in the atmosphere. A) True B) False 48. An organism that becomes a successful pathogen must evade detection by the host's immune system. A) True B) False 49. There are four (4) generations of tissues found in the seed. A) True B) False 50. Insects becam A) True B) False e smaller in size when oxygen levels were 50% higher than today's levels. 51. Endospores are heat resistant structures produce by certain bacteria. A) True B) False 52. Biofilms can form on teeth, contact lenses, replaced joints, and in water pipes. A) True B) False Match the following: A) Nanoarchaeota This was the original source of food for the picture-winged fruit fly in the Hudson Valley regions 53. 54. This type of bacteria is linked to skin diseases, B) Exotoxins 55. This type of bacteria were named according to C) Hawthorn fruit 56. This term refers to the ability of a bacterial to D) Staphlococcus 57. These are often fatal and are released by living E) Toxigenicity respiratory infections, and wound infections. their size. produce toxins within it's host. bacteria.

Explanation / Answer

47. Option (A) true

Carbon dioxide is a major greenhouse gas. When carbon dioxide levels double the greenhouse effect will definitely increse. Due to greenhouse effect the dry areas become drier and the wet becomes wetter. This is because in dry areas due to high evapotranspiration there will be high chances of prolonged drought conditions while in wet areas it tends to more precipitation.

48. Option (A) true

A pathogen is said to be successful only if it escapes the detection of the immune system of the host. For example the HIV avoids detection by completely changing the surface antigens. Some cancer cells avoid detection by forming a layer of healthy cells from the NK cells.

49. Option (B) false

Normally a seed has three generations of tissues. They are

i. Embryo

ii. Seed coat which is a sporophytic tissue

iii. Gametophyte that provide the nutrition

50. Option (B) false

If the oxygen levels increase i.e hyperoxia condition there will be increse in the size of the arthropods ( those using mostly tracheal system) this is clearly evident from the presence of gigantic tracheates in the previous eras. This is because of high efficiency of the tracheal system which causes the growth of the body.

51. Option (A) true

Bacteria of the Phylum Firmicute has the ability to produce the endospores. Bacteria of genus clostridium and bacillus have the ability to produce endospores. Endospores are not real spore but they are formed as a result of division of bactrbact cell inside the cell wall and one side engulfs the other and forms the small endospore which can thrive under any unfavorable conditions. When favourable conditions are present they will again turn to the vegetative state.

52. Option (A) true

Biofilms are the sticky structures that are formed as a result of attachment of various bacteria. They are the organised colonies of the bacteria. If formed on teeth they cause the dental decay. They can form on living or non living structures.

53. C. Hawthorn fruit . The picture winged fruit fly that's present in the Hudson valley region primarily feeds on hawthorn fruit which was found by various zoological surveys.

54.(D) Staphlococcus. The bacteria of staphlococcus is generally found in humans and other animals by causing diseases regarding the skin , respiratory system and also on the wounds of animals .

55. (A) Nanoarcheota . The word nano itself indicates that the organism is small so these are the group of bacteria which are very minute.

56.(E) Toxigenicity is the ability of an organism to produce the toxins .

57. (B)Exotoxins are the toxic substances that are released by several kinds of bacteria which are regarded as highly fatal to the hosts of that bacteria.

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