Plz answer correctly i need the grade bad Describe the function of the pericardial sac around the heart. (2pts)
Describe how the blood vessels (arteries and veins) are adapted to transport blood. State at least three physical adaptations for their function. (3pts)
Why is one side of the heart larger in size. Explain. (1pt)
Explain the two types of blood circulation seen in humans. (2pts)

a. List the 4 chambers of the heart and b. list the valves found in the heart also. (4pts)

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.

explanation:

humans are now responsible for causing changes in the environment that hurt animals and plant species. we take up more space on earth for our homes and cities. we pollute habitats. human activity often changes or destroys the habitats that plants and animals need to survive.

genetic variation will increase because of a new habitat and food source.

explanation: