MSMA (monosodium methanearsonate) is an arsenic-based grass killer. It kills grassy weeds such as crabgrass and goosegrass without harming most turfgrasses. It contains organic arsenic that, according to the University of Tennessee Extension, is less harmful than aspirin.
While open-fit hearing aids are the most popular choice of hearing aids and certainly offer many benefits, they are not for everyone. The best practice before selecting a hearing aid is to have a hearing test done by a qualified hearing healthcare provider. The best style of hearing aid for an individual depends on hearing test results, dexterity, vision, communication needs, lifestyle and what they can afford.
Four Types of Teaching Aids. There are four main types of Teaching Aids 1. Auditory Aids These teaching aids act through ear for which peaceful and calm atmosphere is necessary. Ability to listen attentively should be foster among the students. (i) The Gramophone This teaching aid is used for different purposes. It is useful for the teaching of music and language.