Answer: C

Explanation:

Plant genetic engineering methods were developed over 30 years ago, and since then, genetically modified (GM) crops or transgenic crops have become commercially available and widely adopted in many countries. The first generation GM crops have improved traits such as herbicide-resistant crops (soybean and maize), pest resistance (cotton and maize). Second generation GM crops include higher quality traits, such as higher nutrients. "Golden rice," one of the first GM crops, has been biofortified to overcome vitamin A deficiency. Other biofortification projects include enriching corn, sorghum, cassava and banana plants with enhanced minerals and vitamins. Crops can also be modified to overcome plant viruses or fungi. Hence all the statements are correct.

Answer: C

Explanation:

RNA interference is a gene silencing technique that regulates gene expression in a cell. It is being used to treat a variety of diseases, including cancer, viral infections, and heart disease. Hence statement 1 is correct.

People's cholesterol levels can be reduced through drugs based on RNA interference. For example, using gene silencing technology, a drug has been developed to treat atherosclerosis. This drug uses a type of microRNA that blocks the expression of genes responsible for atherosclerosis. Hence statement 2 is correct.

RNA interference technology can also be used for genetic alteration. For example, using RNA interference, mutations can be induced in cancer cells that cause them to die. Hence statement 3 is not correct.

RNA interference is being used to treat bacterial diseases. For example, RNA interference can be used to prevent the development of antibiotic resistance in bacteria. Hence statement 4 is correct.

Answer: C

Explanation:

Mitochondria are cylindrical, rod-shaped, or spherical structures found in the cytoplasm. This is the respiratory site of cellular respiration. It is also called the 'power house' of the cell. Hence statement 1 is correct.

Mitochondria are the organelles that contain DNA in circular form, and in animals, it is the only organelle other than the nucleus that contains DNA and genes. Sperm contain a small number of mitochondria and mitochondrial genes. In the offspring, the mitochondrial genes are inherited from the mother, thus, a father with a mitochondrial gene defect cannot transmit the disease to his offspring. Hence statement 2 is correct.

Answer: D

Explanation:

Cryogenic engines are used when high amounts of energy are required, such as for spacecraft or rocket launches.

• Spacecraft launch: A lot of energy is required to propel a spacecraft out of Earth's gravity. Cryogenic engines provide high thrust using liquid hydrogen and oxygen, enabling spacecraft to provide the necessary energy.

• High Orbit Satellite Launch: High orbit satellites also require high energy to lift them out of the Earth's atmosphere. Cryogenic engines are used to launch these satellites.

• Geostationary satellite launch: Geostationary satellites require a lot of energy to keep them in a stable orbit around the Earth. Cryogenic engines are also used to launch these satellites and keep them in stable orbit.

• Rocket Launch Vehicles: Rocket launch vehicles are used to launch large satellites or spacecraft. Cryogenic engines are used to launch these vehicles.

• Submarines: Cryogenic engines can be used to provide submarines with the energy needed to remain underwater for long periods of time.

• Power generation: Cryogenic engines can also be used to generate power. However, this is still a developing field.

Answer: A

Explanation:

Machine learning is a type of artificial intelligence that allows machines to learn from past data and create predictive models. Given new data, machine learning systems can correct themselves using statistical models.