Here the triangles formed are: 
ADB, AID, GLD, AIB, BSK, BDE, DEI, BEI, BSJ, LIN, BKJ, ADE, ABE 
KCF, COK, COF, COH, OHF 
OPJ, OSL, FSD, NPE, JEF, AGN, BPL
So, there are in total 25 number of triangles.
Hence, option A is the correct answer.

let present age of Vishal=x years then present age of Aditi=x-25 years

ATQ,

x+x-25=105

2x=130

x=65

present age of Preetam=present age of Aditi + 7

=x-25+7

=65-25+7

=40+7

=47 years

Hence, Option D is the correct answer.

Hence, option C is the correct answer.

● The forked-tailed drongo bird of Africa imitates multiple species’ warning calls to scare off other animals and steal their food. 51 different calls are known to be imitated.

● Drongos in the Kalahari desert use alarm calls in the absence of a predator to cause animals to flee and abandon food, which they eat, getting up to 23% of their food this way.

• Eutrophication is the enrichment of a water body with nutrients, usually with an excess amount of nutrients.
• The excess nutrients cause an algal bloom. The algal bloom blocks the light of the sun from reaching the bottom of the water body.

• The ‘Sun Temple’ of Konark is in the State of Odisha.
• The name Konark derives from the combination of the Sanskrit/Odia language words Kona (corner or angle) and Arka (the sun).
• It is dedicated to the Hindu 'god Surya'.

The monthly incomes of A and B are ₹12000 and ₹8000 respectively.

The ratio of their monthly expenditures is 5 : 3.

Let monthly expenditure of A = 5x

monthly expenditure of B = 3x

According to questions

Monthly expenditure of A =

Saving of A =

Hence, they both save = ₹2000.

Let the marked Price be Rs 100

Discount offered  on marked Price = 10%

After 10% discount ;

price = 100 - (10×100)/100 = Rs. 90

Gain% = 17%

Cost Price =(100×SP)/(100 + profit%)
= (100×90)/(100+17) = 77

After offering 15% discount

New selling Price  = 100 -  (15×100)/100= Rs 85

profit%  = [(85-77)×100]/77 = (8×100)/77 = 10.5%

Glacier: a slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles.

Typhoon: a tropical storm in the region of the Indian or western Pacific oceans.

Avalanche: a mass of snow, ice, and rocks falling rapidly down a mountainside.

Blizzard: a severe snowstorm with high winds.

Hence, option A is the correct answer.

The error is in the segment 'was secure by'. We use past participle after 'be' form of the verb.

Hence, 'secure' should be replaced with 'secured' to form a grammatically correct sentence.

Therefore, option C is the correct answer.