Science 1 Marks Question

The removal of waste products is termed excretion.

The water in which these organisms live brings them food and oxygen as it enters their bodies.

Sweat contains water and salts.

Urine examination determines whether the kidney is working properly or not.

Wrong, the heart has four chambers. Two auricles and two ventricles.

Bladder stores the excretory product released after filtration from kidney and excrete it out at specific times.

Veins.

Arteries.

Yes, skin is an excretory organ as it secretes waste products by releasing sweat from the surface.

Veins do not have thick walls because blood in vein is no longer under pressure but blood emerges from the heart is under high pressure. So arteries have thick walls.

Exchange of substances between arteries and veins occurs via capillaries.

Urea, uric acid and excess water.

Plasma contains large protein molecules, blood cells and nutrients which it circulates throughout the body. It is responsible for the flowing of blood.

Because plant utilise the absorbed water in various activities like photosynthesis, regulation of temperature and for movement of nutrients.

Sports persons expend a lot of energy and, therefore, larger amount of water is evaporated from their bodies. To prevent dehydration they should drink more water.

Sphygmomanometer.

The function of circulatory system is to transport oxygen, carbon dioxide, hormones and excretory wastes from one region to another.

Throbbing that occurs in arteries due to flowing of blood is called pulse or the flow of blood in an artery over a bone is called the pulse.

A stethoscope reads heartbeats as diaphragm amplies the rounds of heartbeat when placed on specific areas.

Kidney is the major excretory organ and nephrons are its functional units.

Extra salts are removed along with water as sweat.

Urine is the mixture of urea and other unwanted salts with water which is needed to be excreted out as its presence in blood can make a person ill.

By soaking the vegetables in water, the skin of the vegetables becomes moist and water starts moving from one cell to another until the vegetables are fresh again.

Pulse rate is equal to the number of heart beats per minute.

Excretory system.

The carbon dioxide is removed by lungs while urea is removed from the body by kidney.

The blood from the heart is transported to all parts of the body by the arteries.

The division of heart into different chambers ensures that there is no intermixing of oxygenated and deoxygenated blood. This ensures a better efficiency of circulation and transportation of oxygen.

Food, water and oxygen are the products that are carried by blood to every part of the body.

The circulatory system consists of three major organs, i.e., blood, blood vessels and heart.

Blood is a fluid tissue which connects all the parts of body with each other.

Plasma.

Pulmonary veins carry oxygenated blood from lungs to heart.

Plants absorb water and minerals from soil by the roots. The root hair absorbs water and dissolved mineral nutrients from the soil. The roots remain in contact with underground water.

Artificial ways of waste removal are used like dialysis which are referred to as artificial kidneys.

Stethoscope.

Hemoglobin is present in red blood cells.

Hydra does not have specialised organs for circulation. Oxygen and food are diffused into the body and undigested material is diffused out.

Xylem-water and minerals.

Valves are present at the opening of auricles into ventricles to prevent backflow of blood.

Pulmonary vein.

The faster heartbeats signify that heart is pumping more blood to the organs as they need increased oxygen and energy supply.

Valves are present in veins to prevent backflow of blood in tissues.

Urea.

The walls of arteries are thick because they carry blood at high pressure.

The rhythmic expansion and contraction of the heart is called heart beat.