Fluid filled sacs in the knee are specifically called Bursa or Bursae. Bursae is plural for Bursa.
A bursa is a closed fluid filled sac that function as a gliding surface to reduce friction between tissues of the body. Knee bursitis occurs when there is irritation or inflammation in one one of the knee bursa. The procedure of removing fluid-filled sac is called bursectomy. When the bursa become infected with bacteria, this condition is called septic bursitis.
Mendel observed that a heterozygote offspring can show the same phenotype as the parent homozygote, so he concluded that there were some traits that dominated over other inherited traits. However, the relationship of genotype to phenotype is rarely as simple as the dominant and recessive patterns described by Mendel.
Answer: Bottom layer of rock
Explanation:
The bottom layer is the layer of the deposition of the sediments in which sedimentation and cementation occurs to form the rocks. These rocks are formed at the lowest horizon of the soil profile. These rocks are also called bedrocks. The layer present above the rock are younger and the layer at the top is the youngest layer. The older layer at the bottom and the younger layer at the top. This phenomena is called law of superimposition.
The clumping together of red blood cells by the action of an antibody is known as agglutination.