General Science Mixed Quiz: Set 181

It is the heat a liquid absorbs to turn into vapour at its boiling point, while its temperature stays the same.

Cardiac muscle shows the cross stripes of skeletal muscle under the microscope, but it is not under the control of the will and it beats rhythmically on its own, driven by the pacemaker of the heart; its cells are branched and joined end to end by intercalated discs, which let…

Only the female Anopheles bites humans for blood, and in doing so it passes the malaria parasite, Plasmodium, into the bloodstream.

Colostrum is the thin yellowish milk secreted in the first days after delivery and is rich in antibodies, especially immunoglobulin A, which pass to the baby and protect it from infection at a stage when its own immune system is immature; this protection is called passive immunity.

After fertilisation the ovary of the flower grows into the fruit, and each ovule inside it develops into a seed.

BCG stands for Bacillus Calmette-Guerin, a live but weakened strain of the bovine tuberculosis bacterium, and in India it is given soon after birth under the Universal Immunisation Programme, mainly to prevent the severe forms of childhood tuberculosis.

Near the horizon, sunlight crosses a much thicker layer of air, and scattering removes most of the blue light before it reaches us.

The genes called cry genes are taken from Bacillus thuringiensis, a bacterium of the soil that forms protein crystals during its spore stage.

Zinc lies in the middle of the reactivity series, so its oxide can be reduced to the metal by heating it with carbon (coke): ZnO + C → Zn + CO.

Auxin made at the shoot tip moves downwards and keeps the lateral buds below it inactive, which is why a gardener who nips off the tip of a hedge plant gets a bushy growth of side branches.

These ducts and glands do not make sperm; they help sperm mature, store and move them, and add the fluid in which sperm swim.

A light year is the distance travelled by light in vacuum in one year, which is about 9.46 times ten to the power twelve kilometres, or roughly nine and a half trillion kilometres.

Platelets, or thrombocytes, release the factors that start blood clotting at a wound. Platelets are tiny cell fragments made from large cells called megakaryocytes in the bone marrow; a healthy adult has about 1.5 to 4.5 lakh of them per cubic millimetre of blood.

Pressure applied to an enclosed liquid is transmitted equally and undiminished in every direction, so a small force on the narrow master cylinder of a brake creates a much larger force on the wide piston at each wheel, which is also how a hydraulic press and a hydraulic lift work.

In every isolated system these three quantities stay constant, and no known process has ever been found to break these laws.

The islets of Langerhans are patches of endocrine tissue in the pancreas, and their beta cells secrete insulin, which lowers the level of glucose in the blood by helping cells take it up and by storing the surplus as glycogen; a lack of insulin causes diabetes mellitus.

By mass, an adult human body has the most oxygen, then carbon, hydrogen and nitrogen. Oxygen makes up about 65 percent of body mass, carbon about 18 percent, hydrogen about 10 percent and nitrogen about 3 percent.

Metal blocks X-rays far more strongly than body tissue, so it spoils the picture. An X-ray image is a shadow picture.

The standard hydrogen electrode has a real, non-zero potential; it is only assigned the value zero by convention. The absolute potential of a single electrode cannot be measured, because any measurement needs a second electrode to complete the circuit.

The eyes of a potato are nodes with buds, and only a stem bears nodes and buds, so they prove that the potato is a modified stem.