While eating peach or pear it is usually seen that stone like structures get entangled in the teeth, what are these stone like structures called?

Bryophytes have root-like structure called…………..

The disc like structure which helps in the transfer of substances to and from the foetus's body is called…………

Fill in the blanks. The disc like structure which helps in the transfer of substances to and from the fetus's body is called _______.

Each granum is made up of many plate like structures placed one above the other like stack of coins.... in which photosynthetic pigments are located & spaces of thylakoid is called...

Read the following paragraph and answer the questions based on it. Rhizobium produce nitrogenous compounds from atmospheric nitrogen. However, for this process of nitrogen fixation, they need leguminous plants like beans, sweet pea, soyabean, etc. as ‘host’. Rhizobium living in root nodules supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates from it. Such a mutually beneficial relationship is called symbiosis. Beans and pulses are rich in proteins due to the nitrogenous compounds made available by Rhizobium. After harvesting a leguminous crop, the left-over roots and other plant parts are deliberately dumped in farm soil to maintain its bacterial population. The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. It has also helped to reduce expenses on fertilizers and thus works to the benefit of farmers. What is provided by the host plant to the Rhizobium bacteria?

Metals get attacked by substances around it such as moisture, acids, etc. Metal is said to 'corrode' due to this attack and the process is called corrosion. Many metals like iron, copper, silver, etc. get corroded. When iron is exposed to moist air, it undergoes corrosion and a reddish brown coloured solid layer is formed on its surface. Corrosion of iron, which is known as rusting, is a serious problem as enormous amount of money is spent every year to replace damaged iron. Similarly, copper reacts with moisture and. CO_(2) in air to form a green coloured coating of basic copper carbonate on its surface. Silver acquires a black colour when exposed to air containing H_(2)S due to the formation of silver sulphide on its surface. Based on the above paragraph, answer the following question. What happens to silver ornaments if they are exposed to air containing H_(2)S gas?

Read the paragraph and answer the questions given below : Locomotion is considered as an important characteristics of the animals. However, animals belonging to Porifera are said to be sedentary. Every other phylum has typical locomotory organs. E.g. Nereis crawls with the help of parapodia, whereas earthworm buries in soil by setae. Spiders have four pairs of walking legs, crab has five while all insects have three pairs of walking legs. The walking legs are also called appendages. Starfish moves with the help of tube feet. Snails and bivalves use muscular foot for locomotion. Birds flying with their spread out wings and fish swimming with their fins, both have spindle-shaped body tapering at both the ends. While flying or swimming such body offers least resistance during locomotion. Mammals have two pairs of limbs while animals like snakes are limbless. Other animals belonging to the class of snakes also have very weak limbs.which make them creep on the ground. Answer the question: What are the locomotory organs in phylum Annelida?

Metals get attacked by substances around it such as moisture, acids, etc. Metal is said to 'corrode' due to this attack and the process is called corrosion. Many metals like iron, copper, silver, etc. get corroded. When iron is exposed to moist air, it undergoes corrosion and a reddish brown coloured solid layer is formed on its surface. Corrosion of iron, which is known as rusting, is a serious problem as enormous amount of money is spent every year to replace damaged iron. Similarly, copper reacts with moisture and. CO_(2) in air to form a green coloured coating of basic copper carbonate on its surface. Silver acquires a black colour when exposed to air containing H_(2)S due to the formation of silver sulphide on its surface. Based on the above paragraph, answer the following question. What is rust?