Science [2 Mark Questions]

The water required by the plants for photosynthesis is absorbed by the roots of the plants from the soil through the process of osmosis. The absorbed water is then transported upward through the xylem vessels to the leaves where it reaches the photosynthetic cells and utilized in photosynthesis.

Blood pressure: The pressure at which the blood is pumped around the body by the heart is called blood pressure. The two factors which expresses the blood pressure a person are systolic pressure and diastolic pressure.

The deficiency of haemoglobin in the blood of a person reduces the oxygen carrying capacity of blood resulting in breathing problems, tiredness and lack of energy.

The process by which green plants make their own food (like glucose) from carbon dioxide and water by using sunlight energy in the presence of chlorophyll is called photosynthesis.

1. Proteins.
2. Starch.
3. Proteins.
4. Fats.

Urea is the main nitrogenous waste in human blood. It is removed from the body in the form of urine through the kidneys.

The conditions for photosynthesis are sunlight, chlorophy ll, carbon-dioxide and water.

Anaerobic respiration takes place in human muscles during vigorous physical exercise because oxygen gets used up faster in the muscle cells than can be supplied by the blood.

1. Circulatory system.
2. Excretory system.
3. Respiratory system.
4. Digestive system.

If the blood pressure of a person is 120/80 it means that the systolic pressure is 120mm Hg and diastolic pressure is 80mm Hg.

Diffusion is insufficient to meet the oxygen requirements of large multicellular organisms like humans because the volume of human body is so big that the oxygen cannot diffuse into all the cells of the human body quickly and oxygen will have to travel large distances to reach each and every cell of the body.

The opening and closing of stomatal pores is controlled by the guard cells, when water flows into the guard cells, they swell, become curved and cause the pore to open whereas when the guard cells lose water, they shrink, become straight and close the stomatal pore.

The function of respiratory system is to breathe in oxygen for respiration (producing energy from food), and to breathe out carbon-dioxide produced by respiration.