The answer is spicules. These
sharp-pointed structures are formed from calcium carbonate skeleton of
the organisms. They can also be formed from silica. They can be big (megascleres),
or microscopic (microscleres). Also dependent on the number of axis on the spicules, they are classified as monoaxon,
triaxon or polyaxon.
Suppose that the proportion of the white crest alleles (r) is given by w and that of the Red crest allele (R) is given by p. We have that p+w=1. The probability that an individual has 2 r alleles is given by w*w since for each allele position the probability is w. Only these individuals have a White phenotype. Hence, we get that w^2=

; the right hand side is the proportion of white birds in the total population. Doing the calculations, this yields that w=0.37. From this, we calculate that p=0.63. The possible ways we have heterozygous individuals are the combinations Rr and rR. The probability for each of those is p*w. Thus, the total probability is 2pw. This is equal to 0.466=0.47. This is the fraction of the future population that is going to be heterozygous assuming the conditions of the Handy-Weinberg equilibrium like random reproductive matching etc.
In most cases, the two major climatic factors affecting the distribution of organisms in terrestrial ecosystems are the amount of water and temperatures. Terrestrial ecosystems rely on the sun's energy to support the growth and metabolism of the organisms. Plants use the sunlight, then they supply the organisms that are higher up the food chain with energy and the structural buildings blocks of life. Water is also essential for the survival of these organisms.
Episodic Memory!
Episodic memory includes personal information on what happened and where.
Hope this helps!