Lunar phases are basically the different positions of the moon that we see throughout its whole cycle, from new moon to full moon, back to new moon. Eclipses, though are more rare phenomena. These occur when the sun, moon, and earth line up at a specific position.
Asteroids are usually dense bodies, with many different formations on their surface. They are also believed to be the largest source of precious metals on our planet.
Comets are bright clouds of gas surrounding a center nucleus that speed toward the sun and heat up at the same time. They contain dust, ice, carbon dioxide, and other gases. As the comet soars toward the sun, the radiation pushes dust particles back, forming the tail they are known for.
Spines primarily have a protective function in plants. The spines can be sharp, and form a physical barrier against herbivores which may want to feed on the plant. Spines however also have other benefits. The spines on a jumping cactus allow segments of the cactus to stick to passing large animals or humans, thereby allowing the cactus to spread to other areas through asexual propagation. Spines are modified leaves, and spines have a much lower surface area than leaves, and therefore can reduce transpirative loss of water by the plant during harsh droughts. Some trees in alpine regions, such as pine trees, have developed spine-like leaves to prevent the accumulation of snow in the branches.
Normally they have equal protons and neutrons
Answer:
The phenotypes are as follows
Purple, full- 9
Purple, constricted- 3
White, full- 3
White, constricted- 1
Genotype of parents are PpFf, each produce the following gametes: PF, Pf, pF and pf.
Explanation:
This is a dihybrid cross involving two distinct genes. One coding for flower color and the other for pod shape. The allele for purple color (P) is dominant over the allele for white color (p) while the allele for full pod (F) is dominant over the allele for constricted pod (f).
In a cross between two heterozygote parents i.e. PpFf × PpFf, each parent will produce the following gametes: PF, Pf, pF and pf. Using these gametes in a punnet square (see attached image) the following 16 offsprings will be produced in a phenotypic ratio: 9:3:3:1
Purple color, full pod- 9
Purple color, constricted pod- 3
White flower, full pod- 3
White flower, constricted pod- 1
A mutation that involves one or a few nucleotides is called
a) mutagen
b) inversion
c) point mutation
d) translocation
Answer:
c) point mutation
Explanation:
When only one or a few nucleotides of a gene are changed by mutation, this is called a point mutation. A point mutation can add one additional nucleotide to the wild type gene or may delete or substitute a nucleotide from it. For example, if a wild type gene sequence is "ATATATATA", then the addition of "C" at the position 4 will change it into "ATACTATATA". This addition of new nucleotide is called point mutation since only one nucleotide is added to the gene. Point mutations can cause serious genetic disorders such as sickle cell anemia.
