Answer;
D. The birds have different mating seasons.
Explanation;
-Different species of birds have different mating or breeding seasons. Evolution has played a role in adjusting the timing of avian(birds) breeding seasons to maximize the number of young produced. The breeding season depends on a number of factors, for example In the temperate, subarctic, and arctic zones, the overriding factor is the availability of food. This varies across all different species of birds, irrespective of other similarities they may have.
Answer:
Hemophilia is a x-linked recessive inherited bleeding disorder. in this disease blood does not clot properly due to the decreased level of blood clotting factor VIII (8) or factor IX (9).
In x-linked recessive condition, the disease is transmitted from father (affected male) to his daughter and mother (affected female) to her son and skip of generation getting affected is also occurs.
- there will be 50% chance of her (S.R.) each son to be affected with hemophilia.
Explanation:
Hemophilia is caused due to mutation of one gene which is responsible for the making of proteins of blood coagulation factor viii or ix. the affected person bleeds continuously from any injury and that can cause serious issues.
here,
grandfather of s.r is affected (xₐy) and grandmother is normal (xx) will produce
↓
s.r's mother who is a carrier (xₐx) [as xₐy and xx will produce 100% carrier xₐx daughter]
↓
s.r's mother is a carrier (xₐx) but her father is normal (xy) will produce,
↓
s.r who has 50% chance of being carrier (xₐx) and 50% chance of being normal (xx) [as she is the only child] and she has a normal (xy) partner, they will give,
↓
- if s.r is a carrier (xₐx) then one of her son will be affected (xₐy) [as xₐx and xy =xₐy]
- if s.r is normal (xx) then her son will be normal (xy) [as xx and xy will give xy]
here,<u> 50% chance of her son to be affected with hemophilia</u> [as S.R of being affected is more considerable].
Hag Fish and Lamprey
Vertebrates are the organism which posses a vertibral column(aka the spine or back bone structure), while the earliest had a head they lacked a spine and jaw, these jawless vertebrae lived 500-600 million years ago. they are the ancestors of bony fish which in time became amphibians and other groups of animals
