General Science Questions (MCQs) for Competitive Examinations

Notes:
Cell theory was first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann. They stated that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells.

Notes:
Some plants have the stem branching out near the base. The stem is hard but not thick. Such plants are called shrubs. Eg: Rose plant. Shrubs have persistent woody stems above the field, unlike herbaceous plants. Shrubs may be evergreen or deciduous. By their numerous stems and shorter height, less than 6 m-10 m long, they are distinguished from trees.

Notes:
Adamsia (Sea anemone), Pennatula (Sea-pen) are examples of Anthozoa Class under Coelenterata Phylum. The organism under this phylum are mostly marine, solitary or colonial, sessile, or free-swimming and radially symmetrical animals. Other examples of Anthozoa class are Meandrina (brain-coral), Fungia, Gorgonia (sea fan or horny coral), etc.

Notes:
Water catchment areas such as forests are continually being destroyed through deforestation to pave way for human settlement. This problem has been brought about by rapid population increase. As a result, there is not enough rain thus causing water shortage.

Notes:
Most of Earth’s oxygen comes from tiny ocean plants – called phytoplankton – that live near the water’s surface and drift with the currents. Like all plants, they photosynthesize – that is, they use sunlight and carbon dioxide to make food. Scientists believe that phytoplankton contribute between 50 to 85 percent of the oxygen in Earth’s atmosphere (National Geographic).

Notes:
Yeast is an important source of most B vitamins (except B12) and folate and contains potassium and magnesium. It is used in the preparation of vitamin B complex tablets. Therefore, seeds have been classified as endospermic with endosperm and nonendospermis without endosperm.

Notes:
The nucleoplasm is the liquid or semi-liquid substance of the nucleus filling the space around the DNA and the nucleoli. It is a type of protoplasm that is made up mostly of water, a mixture of various molecules, and dissolved ions. It is completely enclosed within the nuclear membrane or nuclear envelope.

Notes:
The inner walls of the small intestine have thousands of finger-like outgrowths called villi (singular villus). The villi increases the absorption of the digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.

Notes:
Pneumatophores are spongy erect roots extending above the surface of the water that facilitate the exchange of oxygen and carbon dioxide for the roots. They are specialized root structures that grow out from the water surface where inadequate oxygen required for normal respiration of the roots is present. They are seen in many mangrove species.

Notes:
Pituitary gland is often considered the most impor- tant part of the endocrine system because it produces hormones that control many functions of other endocrine glands. The pituitary gland is often dubbed the “master gland” because its hormones control other parts of the endocrine system, namely the thyroid gland, adrenal glands, ovaries, and testes.