The are 4 glands in the endocrine system. The thyroid gland, pineal gland, parathyroid gland, and the pituitary gland.
Answer:
transporting oxygen and nutrients to the lungs and tissues. forming blood clots to prevent excess blood loss. carrying cells and antibodies that fight infection.
Explanation:
Answer:
Cross-pollination.............
In the Linnean taxonomical system There are more organisms at the species level than at the genus level.
The correct option is D.
Explanation:
Carl Linnaeus is the father of taxonomy. His idea of classification is widely accepted and called as modern classification.
He categorized 7 levels based on the hierarchy as Kingdom, phylum , class, order, family, genus, species.
The Kingdom Animalia is the highest level of classification and species comes last.
The binomial nomenclature by him has made it very popular where distinguished species are categorized and is universal. In binomial nomenclature genus comes first (starts with capital letter) and species comes later (starts with small letter).
One genus will have many species. for example:
African lion Panthera leo (genus species)
Asian lion Panthera leo leo
So one genus will have many species in it.
Answer:
Sex linked trait
Explanation:
Sex linkage is the phenomenon in which the expression of genes depends on the gender of the organisms because genes for specific traits are located on the sex chromosomes of organisms. If repeated crosses of the fish indicate the pattern that long tail fins appear only in males and not in females, it means the trait is linked to the male sex.
What are sex chromosomes:
They are usually a pair of chromosomes present in higher organisms like humans and other mammals that combine during fertilization of male and female gametes and determine the sex of offspring. In humans they are X and Y chromosomes and when there is an XX offspring, she will e female and when there will be XY offspring , he will be male.
Significance:
- Now there are some genes that are present only on sex chromosomes of the organisms like genes for beard are present in human Y chromosome of men, However,genes found on the X chromosome can be found in either males or females.
- Sex linked genetic disorders are very common in human males because males receive only one copy of X chromosome while females receive two copies. So only one copy of defective gene is enough for the expression of disease in males while in women two copies are needed if the trait is recessive.
- For example: There is a disease called hemophilia in which the blood is unable to clot even after minor injuries and can be life threatening.
- Hemophilia is an X linked recessive disorder and is an example of sex linked traits controlled by sex linked genes.
Hope it helps!
