Questions

Silicon carbide is used in Cutting very hard substances.

Salivary glands of man are 3 pairs = 6. They are one pair of parotid glands, one pair of sub-maxillary or sub-mandibular glands and one pair of sub-lingual glands.

Black  surfaces are good emitters of heat ( They are also good absorbers of heat). If the black surface is rough too, the emitting will be better. So (b) is the correct answer. Shining surfaces reflect back radiation. So if the black surface is also shining the effectiveness of emitting heat is lessened.

Shipment movement information is captured each time a tracking label is scanned in the UPS delivery system. There may be several days between scans if the shipment is going cross-country or moving between countries.

Destination Scan: The shipment has arrived at the local UPS facility responsible for final delivery.

Arrival Scan: The shipment has arrived at a UPS facility.

Departure Scan: The shipment has departed a UPS facility and is on its way to the next UPS facility.

Origin Scan: UPS has received the shipment.

Molecular compounds are those with covalent bonds between the elements and those elements are typically non metals.

Here in the given options, Ar is an element. NaI has an ionic bond. Hence, N2O4 has a covalent bond between the two non metals and is a molecular compound.

Oxygen is the final electron acceptor of cellular respiration.