Quadrat method is used for estimating the number of individuals in an area. In this method, a large square area on the ground or water surface is marked, call it an enclave. The number of animals present in this enclave is counted. Then by assuming that the animals are less migratory and are uniformly distributed, their number for a large area is estimated by the use of unitary method of calculation. Example a 4 square feet area has 2 snails, then a 1000 square feet area will have (1000 x 2)/4, i.e, 500 snails in it. Fishes can be counted using this method only if they are confined in a small water body like a lake or a pond. Rivers are flowing so the fishes may move along its length which can give us an underestimate or an overestimate of their numbers. Sea has its depth and huge area, and fishes can be moving randomly in it. Hence this method will not work for river and sea fishes.
Answer:
A phosphate backbone is the portion of the DNA double helix that provides structural support to the molecule. DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
Answer: A) C)
Explanation:
Sedimentary rocks are formed and made in one situation when sediment is deposited out of ice, wind, gravity, air, and water.
That sediment is formed when it comes to erosion and weathering. It is happening with breakdown of rock into some loose material and that is why correct answers are erosion and weathering.
The answer is false explanation: while environment may slowly cause evolution it doesn’t change the overall genetic make up
Answer:
Cellular differentiation.
Explanation:
Cellular differentiation is the process in which a cell changes from one call type to another. Usually, the cell changes to a more specialized type. Differentiation of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types.
