Question

Some of the characteristic of Bt cotton are:
A. High yield and production of toxic protein crystals which kill dipteran pests
B. High yield and resistance to silkworms.
C. Long Fibres and resistance to aphids.
D. Medium yield, long fibre and resistance to beetle pests.

Answer 1

Bt Crops are transgenic plants that contain the same toxin as the Bacillus thuringiensis bacterium in the plant cell, protecting the plants from pests. The bacterium produces poisonous proteins known as "cry proteins" that are secreted by the bacteria. Cotton, brinjal, corn, and other Bt crops are examples. Bacillus thuringiensis is a gram-positive, spore-forming bacterium found mostly in soil. It produces proteins that are harmful to insects, as previously mentioned.

Complete explanation:
Option A: The Gram-positive bacterium Bacillus thuringiensis (Bt) develops crystals during sporulation. In the Bacillus, these crystals are made up of one or a small number of $130{\text{ }}kDa$ protoxins known as crystal proteins, which exist as inactive protoxin. These proteins are highly specific and active insecticides (bollworms). It was made by inserting the Cry I and Cry II protein genes into cotton plants. Since Bt toxin is a particular insecticide that kills only its specific hosts, the presence of this gene confers resistance to Lepidoptera (bollworm), not aphids or dipteran insects. Bt cotton also resulted in higher yields and longer fibres.
So, option A is correct.
Option B: Bt cotton is a pest-resistant cotton variety produced by a genetically modified organism (GMO) that produces an insecticide to fight bollworm.
So, option B is incorrect.
Option C: Many cotton pests, such as plant bugs, stink bugs, and aphids, are ineffective against Bt cotton; depending on the circumstances, insecticides may be necessary for prevention.
So, option C is incorrect.
Option D: Cotton that has been genetically engineered to produce a high yield while still being resistant to bollworms is known as Bt cotton.
So, option D is incorrect.

Hence, Option A is the correct answer.

Note:
Bt cotton is a pest-resistant cotton variety produced by a genetically modified organism (GMO) that produces an insecticide to fight bollworm. To protect the plants from bollworm, a major pest of cotton, the Bt cotton variety has been genetically modified with the Bt gene. Worms that live on Bt cotton leaves become lethargic and sleepy, causing less harm to the plants. When the worms eat the plant, they ingest the toxic proteins formed by the crops, which kills them. Pest resistance, herbicide tolerance, high yield, and resistance to bollworm infestation are all advantages of Bt cotton.