Answer:
20 ( B )
Explanation:
Given data:
a and b are 10 map units apart
b and c are 20 map units apart
a and c = 30 map units apart
<em>condition </em>; Triple heterozygote testcrossed
number of progeny = 1000
<u>Determine the number of double crossover result </u>
P( crossover between a and b ) = 10/100 = 0.1
P( crossover between b and c ) = 20/100 = 0.2
p( double crossover ) = 0.1 * 0.2 = 0.02
hence number of double crossovers = number of progeny * 0.02
= 1000 * 0.02 = 20
Answer:
A. These homologous structures indicate that these four organisms all share a common ancestor.
Explanation:
Homologous structures mean the organs will have similar structure, but not necessarily function (human arm vs whale's flipper). While analogous structures are similar in function but not structure (wings of an airplane vs wings of a bird). Since the question states that they are similar in skeletal structure, we know they must be homologous structures, thereby eliminating B and C. D is not a choice because the question does not provide anything about the order of evolution. Therefore the answer is A. These homologous structures indicate that these four organisms all share a common ancestor.
Answer:
protein
Explanation:
a specific protein tht functions in one or more types of cells in the body.
Answer:
they are Na+, K+ and Ca2+ ion channels.
Explanation:
Ionotropic acetylcholine receptors are also called nicotinic acetylcholine receptors because beside acetylcholine (Ch) they respond to nicotine. These receptors are primary receptors in muscle for motor nerve-muscle communication that controls muscle contraction.
Two molecules of ACh are required for receptor to open. Since the receptors are linked to ion channels, the channels open. Opening of the channel allows positively charged ions to move across it: sodium enters the cell and potassium exits.
