Answer:
The water molecules in ice are considerably far apart as compared to cold water of 4 degrees centigrade and below. This, therefore, makes ice less dense than water at these temperatures (because they are fewer water molecules in ice per unit volume). This is why ice floats on cold water below 4 degrees centigrade. Ice, being a bad conductor of heat, shields the water below an ice sheet from excessive heat loss to the atmosphere. This is why water remains liquid below an ice sheet protecting the marine life below from complete freezing.
The liver plays an important role in the food digestion. The liver secretes bile juice which helps in the digestion of the fats. In the absence of digestion, this bile is stored in the gall bladder. The bile juice is the yellowish fluid, which aids in the digestion of fats (occurring in the small intestine) by emulsifying the fats molecules. the emulsification of these fat molecules is critical for their digestion, and absorption. Hence, the liver secretes bile juice and acts to emulsify the fat in the lumen of the small intestine.
Answer:
Punnett square is a square diagram which is used to predict the genotype of the offspring produced by particular cross.
Let P and p be the alleles of the gene responsible for the flower colors in a plant.
The genotype of both the parents is given as heterozygous that is, Pp.
Two types of gametes would be formed P and p.
The cross is shown in the image below.
The cross would be result in offspring with three types of genotypes PP, Pp and pp in 1:2:1.
The genes in a population give forth the genetic variability across a population (genotypes). In addition, occasional mutations of these genes in a population increase this genetic variability. Hovever, natural selection only favours reproduction of individuals with genes that are favourable in the environment/habitat. Therefore, natural selection has no foresight but is rather pegged on being an ‘opportunistic’ process.
The digestive system breaks down the food we eat while the circulatory system transports the tiny particles to each cell in the body.
