Which group of plants contains the least number of species?

A prospective groom, who is healthy, has a sister with cystic fibrosis (CF), an autosomal recessive disease. Their parents are n

son4ous [18]

Answer:

Explanation:

From the given information:

Since the parent are normal; Let assume that their trait is Pp

The affected sister will be recessive in nature, so the trait will be pp

Now, the husband who is the groom will be a carrier with a probability of 2/3 since her sister is affected.

Also, the wife will be carrying a heterozygous trait since she is normal as well.

However, using Hardy-Weinberg assumption:

$q^2 = \dfrac{1}{2500}= 0.0004$

$q = \sqrt{0.0004}$

q = 0.02

Recall that:

$p+q =1 \\ p = 1 - q \\p = 1 - 0.02 \\p = 0.98\\$

Thus, $p^2 = (0.98)^2$

$p^2 = 0.9604$

$2pq = 2 \times 0.98 \times 0.022$

2pq = 0.0392

Finally, the required probability that there will be an affected offspring amongst the family is:

$= \dfrac{1}{4} \times \dfrac{2}{3} \times 0.0392$

$= \dfrac{1}{153}$

3 0

3 years ago

Arrange the following steps for contraction in the correct sequence.

Kryger [21]

Answer:

Explanation:

Muscle contraction is stimulated by the movement of an action potential moving along a nerve fiber to the muscles. This event follow some series of process before being stimulated.

1. The impulse arrives at the synapse and travels through the transverse tubules.

2. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.

3. Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites.

4. Tropomyosin molecules bind to exposed active sites, linking actin and myosin.

5. Thin filaments are pulled over the thick filaments.

6. The muscle fiber shortens and contracts.

3 0

3 years ago

As habitats change, populations of northern pine trees that were once separated can now exchange pollen. This exchange of genes

Simora [160]

Answer:

Gene flow

Explanation:

Evolution is the changes seen in the growth, development, features of a certain group of species during the cause of time. Evolution causes changes in the gene frequency of species from one generation to the next generation.

There are 5 important mechanisms of evolution and they are: Gene flow, mutation, genetic drift, natural selection and non random mating.

Gene flow as a mechanism of evolution is the exchange or transfer of genes between a group of species as they move from one place to another. Gene flow can either increase the rate of evolution or decrease it.

6 0

3 years ago

Help please asap!!!!!!!!!!!!!!!!!!!

Mazyrski [523]

Answer:

Basidiomycotes

the second one

Explanation:

3 0

3 years ago

Rank the following in order from most general to most specific: 1. gametic isolation 2. reproductive isolating mechanism 3. sper

mihalych1998 [28]

<h2>Reproductive Method </h2>

Explanation:

The rank in order from the most specific which is following .

(1) Reproductive isolating mechanism

(2) Sperm-egg incompatibility in sea urchins

(3) Gametic isolation 

(4)Prezygotic isolating mechanism

(1) Reproductive isolating mechanism- The components of regenerative confinement are an assortment of transformative instruments, practices and physiological procedures basic for speciation. They keep individuals from various species from delivering posterity, or guarantee that any posterity are sterile.

(2) Sperm-egg contradiction in ocean urchins- Bindin is a gamete acknowledgment protein known to control species-explicit sperm-egg grip and layer combination in ocean urchins.

(3)Gametic isolation - Prezygotic hindrances keep preparation from occurring. Gametic disengagement is a sort of prezygotic hindrance where the gametes (egg and sperm) come into contact, yet no preparation happens. Gametes might be not able to remember each other in various species

(4) Prezygotic isolating mechanism- while postzygotic segregation forestalls the arrangement of rich posterity. Prezygotic systems incorporate environment segregation, mating seasons, "mechanical" disconnection, gamete detachment and conduct seclusion.

4 0

3 years ago