List 3 ways soils are classified​

Soils are composed of mixtures of mineral and organic materials, but are classified according to the size of their mineral particles. The three main texture groups are sandy, silty, and clay.

Sandy soil contains particles that can be seen with the naked eye and feels gritty when rubbed between the thumb and forefinger. Sandy soils will generally not stick together when wet.

Silty soil contains particles, which are smaller than sand particles but larger than clay particles. Silt feels powdery when rubbed between the thumb and forefinger. Silty soil sticks together when wet, but will not hold its shape after it is dry.

Clay soil contains the smallest particle size. Clay particles form a sticky soil when wet and will generally hold a shape after drying. Soils are rarely composed of just sand, silt, or clay. They are usually a mixture of the three with a larger percentage of one size of particles.

Depending upon the average grain-size and the conditions under which soils are formed and deposited in their natural state, they may be categorized into following types on the basis of their structure: In the grain-size classification, soils are designated according to the grain-size or particle-size. The more common classification systems are enlisted below: Geological Classification

Classification by Structure

Classification based on Grain-size

Unified Soil Classification System

Preliminary Classification by soil types

Based on the agencies responsible for their present state, soils may be classified under following types:  Residual Soils

Transported Soils:

Alluvial or sedimentary soils

Aeolian soils

Glacial soils

Lacustrine soils

Marine soils.

Then you have inorganic and organic soils.

Explanation:

c is the answer to this question. altitude affects the weather because air molecules evaporate.

we solve the problem using the hardy-wineberg equation.

let us start with the homozygous recessive proportion of individuals with sickle cell anaemia,

we have the proportion as q² = 0.25.

∴ q = 0.5 (frequency of hbs in population)

further,

solving for the frequency of normal cell by using the fact that,

p + q = 1

∴ p = 1 - 0.5 = 1 - 0.5 = 0.5

now we can calculate 2pq in p² + 2pq + q², which is the frequency for heterozygous carriers of sickle cell anaemia,

∴ 2pq = 2 x 0.5 x 0.5 = 0.5

and the homozygous normal cell individuals proportion is given by the expression,

∴ p² = 0.5² = 0.25

hence, the carriers for sickle cell anaemia are in proportion, 0.5, or 50%.