Explanation

• Water vascular system in echinoderms used for Respiration
• ***
• The Water Vascular system in echinoderms is also used for locomotion, food, and waste transportation.
• The water vascular system helps in respiration, as the gaseous exchange takes place on the thin wall of feet tubes.
• The system consists of a central ring canal and radial canals extending along each arm
  

Explanation

Pyrimidine: A nitrogenous base similar to benzene (a six-membered ring) and includes cytosine, thymine, and uracil as bases used for DNA or RNA.

Adenine is a purine nucleobase

Adenine, guanine, and cytosine are common nitrogenous bases present in both DNA and RNA

Explanation

In Mendel's pea plant experiments,

When he crossed purebred pea plants with contrasting traits (like purple and white flowers),

The F1 generation offspring all exhibited the dominant trait (purple flowers in this case).

The recessive trait (white flowers) disappeared in the F1 generation but reappeared in the F2 generation when the F1 plants self-fertilized. T

his reappearance of the recessive trait in the F2 generation confirmed that the recessive allele was still present in the F1 generation, just masked by the dominant allele. 

Explanation

• Meiosis is a type of cell division that occurs in spore-producing organisms, such as plants and fungi, to produce spores.
• In meiosis, a diploid spore mother cell (sporocyte) undergoes two successive cell divisions (meiosis I and meiosis II) to produce four haploid spores.

Explanation

The Law of Independent Assortment states that alleles for different traits are segregated independently of one another during gamete formation.

This is illustrated in a dihybrid cross where two pairs of contrasting traits are examined.

Explanation

Animals are classified into two main groups:

1. Invertebrates (animals without a backbone). Examples: insects, spiders, squids, octopuses, starfish, corals, worm
2. Vertebrates (animals with a backbone. Examples: fish, amphibians, reptiles, birds, mammals (including humans)

Explanation

A palindromic sequence reads the same forwards and backwards.

Given the sequence "CTTAAG", the complementary palindromic sequence is "GAATTC". 

In DNA, A pairs with T and C pairs with G. 

When reading the complementary strand from 5' to 3', the sequence becomes "GAATTC", which is the same as the original sequence read from 5' to 3'. 

Explanation

Meiosis II is the second division in the process of meiosis, which reduces the number of chromosomes in a cell by half.

If a cell starts with 42 chromosomes in telophase II, then each daughter cell will have 21 chromosomes

Because meiosis II divides the chromosomes into four haploid cells. 

Explanation

Meiosis is a specialized type of cell division that produces gametes (sperm and egg cells).

It reduces the number of chromosomes in the daughter cells by half, ensuring that each gamete has only one copy of each chromosome.

This is crucial for sexual reproduction, as the fusion of two haploid gametes during fertilization restores the diploid chromosome number in the zygote. 

Explanation

Thymine is the nitrogenous base which is not present in RNA

Thymine is one of the four nucleobases found in DNA (along with adenine, guanine, and cytosine)

Whereas RNA contains uracil (U) instead of thymine.

RNA uses uracil as a complementary base to adenine during transcription,

while DNA uses thymine as a complementary base to adenine during replication.