Question Discussion & Solution

Binary search algorithm:

Binary search algorithm is used to find an element in an already sorted array.

STEPS 1:

It finds the middle element of the array and compare the element with the element to be searched, if

it matches then return true.

STEPS 2:

If not, then divide the array into two halves in which if element to be search is less than middle

element then search takes place in left part otherwise search in right half.

STEP 3:

Repeat this process, until you get the element.

Explanation:

Best case of Binary search occurs when element to be searched is the middle element of the array.

Then in that case, it just simply compares the element with the middle element, if matches then return

true.  Comparing with the one element will take only O(1) time complexity.

Best Case: Search 35 in below give array

T(n) = O(1)

If '+' means 'divide by', '-' means 'add to', '×' means 'subtract from' and '/' means 'multiply by',

[{(20 × 6) × (7 / 2)} + (3 - 2)] / 5

We put the right symbol given is the question-

= [{(20 - 6) - (7 × 2)} / (3 + 2)] × 5

Now apply BODMAS rule

= [{14 - 14} / 5] × 5

= [0 / 5] × 5

= 0

Hence, "0" is the correct answer.

Explanation:

• Pulses are considered to be nitrogen-fixing crops as they have root nodules onto which symbiotic nitrogen-fixing bacteria like Rhizobium get attached and fix atmospheric nitrogen
• Whereas, Cereals are the crops that demand a lot of nitrogen thus after harvest the soil becomes deficient in nitrogen, so to compensate for this deficiency a pulse crop is grown between two cereal crops
• This practice of growing different food crops alternatively in the same field is called Crop Rotation

Important Points 

Crop Rotation

• Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons
• It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant pests and weeds.
• Crop rotation involves planting a sequence of different kinds of crops in a location over a number of seasons.
• Rotating crops helps maintain or improve soil health and maintain or increase the productivity of the farm over time
• A diverse crop rotation gives the soil microbes different food sources, which ultimately makes soil healthier.

Explanation:

• Plants that grow in the desert have to withstand long dry spells of summer and extreme weather condition
• Hence their leaves stem and roots get modified to prevent loss of excess water and to store water
• Some common adaptation seen in desert plants are:
• 'they have a long root that goes deep in search of water
• they have reduced or very few leaves
• The stem is modified to store water
• Additionally, leaves may turn into spines to protect from predators

Additional Information

• Desert Oak is a tree that is found in  Australia.
• It is found in the dry and arid regions of Australia
• It grows almost 10 ft tall
• It has very few leaves
• Its roots go very deep in search of water
• This water is stored in the tree trunk. Local people use a thin pipe to drink this water.

• Scientific Name: Allocasuarina decaisneana 

• The suspensions that hand from branches are nothing but modifies leaves in order to reduce water loss

The correct answer is Wheat.

Key Points

Concept-

• A wide range of fungal, bacterial, and viral pathogens, affect the yield of cultivated crop species, especially in tropical climates.
• Crop losses can often be significant, up to 20-30 per cent, or sometimes even total.
• In this situation, the breeding and development of cultivars resistant to disease enhance food production.
• This also helps reduce the dependence on the use of fungicides and bacteriocides.

Explanation-

• Resistance of the host plant is the ability to prevent the pathogen from causing disease and is determined by the genetic constitution of the host plant.
• Before breeding is undertaken, it is important to know about the causative organism and the mode of transmission.
• Some of the diseases caused by-
  • Fungi are rusts, e.g., brown rust of wheat, red rot of sugarcane, and late blight of potato.
  • Bacteria – black rot of crucifers.
  • Viruses – tobacco mosaic, turnip mosaic, etc.
• Brown rust of wheat is caused by the fungus Puccinia triticina.

Therefore the brown rust is the disease of wheat.

Additional Information

• Red rot is the disease of sugarcane.
• Late blight is the disease of potatoes.
• Mosaic virus is the disease of turnip.