What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?
a. 3:1
b. 9:3:3:1
c. 1:1:1:1
d. 1:2:1
e. 9:4:2:1
Answer:
c. 1:1:1:1
Explanation:
When a heterozygous individual for two genes is test crossed with a double homozygous recessive individual, the progeny is obtained in 1:1:1:1 phenotypic ratio. This occurs as the heterozygous dominant individual forms four types of gametes in 1:1:1:1 ratio while the homozygous recessive individual would form only one type of gamete having one recessive allele for each gene.
For example, a test cross between TtRr (tall and red) and ttrr (short and white) would produce a progeny in following ratio=
1 tall, red: 1 tall, white: 1 short, red: 1 short, white
Here, T= tall, t= short, R= red, r= white
Answer: anagenesis
Explanation:
Evolution in this species has occured within the lineage of a single population
hope this helps : ))
Answer:
it would help them thrive
Explanation:
because it anables them to catch more with there stronger faster necks
The Biblical flood would have caused the death of all life on earth, except for those on the arc, which would have resulted in fossils that are now found. Fossils being found in different layers of rocks could have been a result of how they settled as the waters receded.
Answer:
poliinators and flagellated sperm
Explanation:
Cycads (phylum Cycadophyta) together with Ginkgophyta, Gnetophyta, Pinophyta, Pteridospermales and Cordaitales belong to the gymnosperms (naked seed-producing plants). They are different than angiosperms which produce encased seeds within an ovary.
Cycads (but also Ginkgo) produce swimming sperm that is different than all other groups which produce sperm without swimming flagella.
Also, unlike other groups of gymnosperms, cycads have specialized pollinators, beetls.
