Answer no 1:
The part labelled A is the upper epidermis . The main function of the epidermis is to protect the structure of the leaf.
The part labelled B is palisade tissues. These are the sites where the chlorophyll are present.
The part labelled C are the air spaces in the spongy mesophyll tissue. They allow carbon dioxide to move freely.
The part labelled D are the vascular tissues which transport water and food.
Answer No 20:
The correct option is B) Most of the carbohydrates are made in the palisade mesophyll.
The palisade mesophyll comprises of chloroplast which are the sites where photosynthesis takes place. Hence, these will be the sites where carbohydrates will be manufactured.
Answer No 21)
The correct option is A) upper epidermis
As upper epidermis is the first layer of leaf, sunlight will enter through it and be trapped by the chlorophyll present in the palisade mesophyll cells.
Answer:
Wild forest fires cause extensive damage to flora and fauna and result in the destruction of man-made property in and around the area of the fire. To maintain the health of the forest and prevent the large wild forest people or man]nagers use prescribe fire or controlled fired when there is no risk of loss of life and resources.
These controlled fires are used by forest officials and fire managers to prevent or keep wildfires at bay. It helps in cleared-off areas by playing the role of a barrier for fire from spreading further.
There is always the risk of flora fauna and the life of wild animals. They can get killed and lose their habitat and the smoke rose from this fire causes for environmental concern too.
Density is a derived unit because it's not reported as a pure unit. (A pure unit would be something like kilograms or meters.) In contrast, the units for density are kg/m3. Density is the ratio of mass to volume; mass has the unit 'kilograms' (kg) and the unit for volume is cubic meters (m3).
Density is an intensive property, which means the amount of the material is irrelevant. The density of a substance is constant.