Dna proofreading. DNA excision repair. The rezponsible enzyme (d)
Answer:
fills with blood during arousal and causes an erection.
Explanation:
The corpus spongiosum is a mass of tissue present in the under part of the penis (male sexual structure) that is actively responsible for erection of the penis. The corpus spongiosum, in conjunction with the corpus carvernosa works to maintain erection of the penis in males.
During sexual arousal, the corpus spongiosum, which surrounds the urethra (passage for urine and semen) helps keep the urethra open for semen to be released while the carvernosa becomes filled with blood. This constant flow of blood into the carvernosa makes the penis enlarge and assume an erect position.
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:
1. symbiont
Explanation:
Symbionts are organisms interacting in a biological relationship that can be of the type mutualistic, commensalistic, or parasitic
In this case, there is a relationship of commensalism between two organisms: the human and the bacterium.
Commensalism is a relationship between two symbionts where one benefits and the other is not harmed or helped. Commensalism it is derived from the word commensal (old french), used for human social interaction. Sometimes the word commensal is used in biology, however, the term symbiont is used more frequently to refer biological relationships.
In general terms it is called data entry
