Explanation:
Fertilization, pictured in Figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. The egg and sperm each contain one set of chromosomes. To ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. In mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. When a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. In placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in Figure 24.23b. The fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. The nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.
Answer:
Eye color depends upon the amount of melanin pigment in the eye.
Explanation:
- Melanin is a brown pigment that is responsible of eye color in the iris.
- The genes are located next to the OCA2 gene.
- When the amount of melanin is in less amount in the iris, it causes change in eye color that may be grey, hazel or blue.
- But when the quantity of melanin is very least,it causes blue color in the iris.
- Blue color is also caused by genetic mutation in an individual.
Answer:
A) bat wing and human hand
Explanation:
Homology in biology is existence of the shared ancestry between the pair of structures or the genes present in the different taxa.
<u>The most common example of the homologous structures is forelimbs of the vertebrates, where wings of the bats, arms of the primates, front flippers of the whales and forelegs of the dogs and the horses are all derived from same ancestral tetrapod structure. </u>
Homologous structures can be explained by evolutionary biology which states that these are adapted to the different purposes as result of the descent with the modification from common ancestor.
Answer:
Petroleum, also called crude oil, is a fossil fuel. Like coal and natural gas, petroleum was formed from the remains of ancient marine organisms, such as plants, algae, and bacteria. ... Millions of years ago, algae and plants lived in shallow seas
Walking off paths, lighting fires, & feeding wildlife
