Q.4. Answer the following question in brief:
(1) Write a short note: pitch of the sound with figure,
(2) State the consequence of deforestation in detail.
(3) How can the fire be controlled?
(4) Write short note on Nucleus of a cell
(5) Explain: oviparous and viviparous animals.
(6) List the changes in the body that take place at puberty.
Answers
Answer:
1) : Frequency of a wave determines its pitch.
Pitch is a characteristic of a sound that depend on the frequency received by a human ear
2: The loss of trees and other vegetation can cause climate change, desertification, soil erosion, fewer crops, flooding, increased greenhouse gases in the atmosphere, and a host of problems for indigenous people.
3: The configuration of some fuels, such as coal and baled waste paper, result in a deep seated and burrowing fire, resulting in less effective fire control by the application of water on the outer surfaces of the fuel. Class B fires should be extinguished with foam, powder, or carbon dioxide extinguishers.
4 : The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
5: Oviparous and viviparous are such two methods. ... This means oviparous animals lay eggs. These eggs develop and hatch into young individuals. In contrast, viviparous animals are born as live young individuals. Therefore, they do not lay eggs.
6: Sudden increase in height.
Change in body shape
Change in voice. In boys' voices become deep and harsh, in girls it is a high pitched voice.
Increased activity of sweat and sebaceous glands.
Reproductive organs begin to mature.
Appearance of secondary sexual characteristics.
Development and enlargement of breasts.
Hair develops under the armpit and in the pubic regions.
Hips broaden and pelvic region widens.
Initiation of menstrual cycle.
Deposition of fat around hips.